Question: I’m part of a group of four people who carpool 265 miles round trip to a once-a-month workshop. We take turns driving our own cars - except for one guy, Steve. He says he can’t because he travels an extra 100 miles round trip to meet up with us, and that’s too much driving. Steve does pay for a quarter of the gas each trip, but I don’t think that’s enough. One of the other drivers agrees with me; the other doesn’t think it’s important. Who’s right?

Answer: Certainly not Steve. As a car owner himself, he surely understands that paying for gas is only part of the cost of operating a vehicle. Insurance, maintenance, depreciation - these things add up. As a matter of principle, Steve has an obligation to figure out the true cost of that 265-mile journey and kick in his fair share.

Here’s an estimate of how badly he’s underpaying. Let’s say each of your cars gets 20 miles to the gallon and gas costs $3.85 a gallon. Then the gas outlay for the round trip totals about $51. But the Internal Revenue Service, which is fairly reliable on this point, estimates the full cost of operating a car at 51¢ a mile. That makes the actual cost of the round trip about $135, not $51 - and puts Steve’s fair share not at the $12.75 he’s paying now but at $33.75. So Steve is shorting the owner of the car about $20 a trip, not to mention the occasional thank-you gifts he should be giving each of you for serving as his chauffeur.

A reasonable question, though, is whether 20 bucks is worth making an issue of. Only you and your fellow drivers can answer that. But if we were in the car pool, we’d vote for telling Steve he needs to buy lunch.

E-mail our ethicists, authors of Isn’t It Their Turn to Pick Up the Check? (Free Press), at right_thing@moneymail.com.

Question: I was at standing on a pier recently when my hat blew into the lake. A nice kid, maybe 9 or 10 years old, swam out and got it for me. I thanked him appreciatively and also thanked his mother, who was nearby. A friend says a “thank you” wasn’t enough - that I should have given the boy ten bucks, or maybe treated him and his friends to ice cream cones. What do you think?

Answer: What’s next? Tipping the kid who gives you his seat on a bus?

Look, this boy wasn’t a beach concession employee and he wasn’t performing the kind of service people are paid for. He was doing a good deed, not bringing you a cocktail. For that he deserves what any stranger deserves for a kindness: your sincere thanks, not a payment.

No doubt your friend believes the boy’s virtuous behavior should be reinforced. Indeed it should, but your thanks and his mother’s praise are the appropriate reinforcement. Give the kid cash or treat to a round of ice cream cones and you risk encouraging him to think that a good deed involves a quid pro quo. Instead what he should be learning is that virtue is its own reward.

And what about reciprocating his kindness? That’s where age really matters. Had an adult rescued your hat, offering him or her an ice cream - or a beer - would have been an unnecessary but gracious gesture. The difference here is that someone old enough for a beer is presumably old enough not to come away from the experience believing that performing a good deed automatically gives you a shot at a score.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: Before my son got married, my wife and I told his fiancée’s parents that, in addition to hosting the rehearsal dinner, we’d pay for one-third of the cost of the wedding (we had a general sense of the overall budget). They were very appreciative and agreed to send us an accounting of expenses post-event. Well, we’ve received it, and it looks to us as if they padded the bill. What should we do?

Answer: Be grateful you didn’t offer to pay for half.

Seriously, the first thing to do is everything that discretion allows to determine the actual cost of the event. That means calling all the service providers involved - the caterer, the florist, the band and everyone else - and asking what each of them would charge for a wedding like your son’s. In short, nail down the numbers.

Then if they don’t add up, say to the bride’s parents in your most apologetic voice, “I’m just wondering if there’s been some sort of error. We’d been expecting the wedding to cost around [whatever you believe it actually cost]. Could you double-check the math to be certain there’s been no mistake?” In other words, without being accusatory, give them a face-saving opportunity to adjust the bill.

And if they don’t? While it’s perfectly ethical to challenge any bill you believe to be incorrect, you have another obligation here: to support your son’s marriage. For the sake of family harmony, hold your nose, write the check and keep your suspicions to yourselves. But never agree to share the cost of anything with these people in the future.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: I love my wife, but her inability to keep her mouth shut about money has become a real problem. She’s got a couple of relatives whose hands come out whenever they hear that I’ve gotten a raise or that we’ve treated ourselves, for example, to a big screen TV. I handle our finances, and I’m beginning to think I shouldn’t be telling Heather as much about them as I do. Under the circumstances, would this be wrong?

Answer: As any 19th century novelist could tell your wife, a family without secrets is a family without money. It’s too bad Heather hasn’t yet figured out that discretion is a virtue, and for this you have our sympathy.

Unfortunately, the solution you propose – keeping Heather in the dark – while tempting, isn’t kosher. Knowledge is power, which is why spouses have a right to know as much as they want to know about their household’s financial situation. Plus, your plan is impractical: What are you going to do, misrepresent to your wife the cost of every expensive thing you buy or hotel room you stay in?

What needs to change here is not what you’re doing, but what Heather’s doing. She should stop sharing personal financial information with the wrong people. Especially given what you’ve said about her family, her immature behavior is inviting trouble as surely as if she were blowing every paycheck on a high-end hobby or insisting that you invest your savings in penny stocks.

We know, we know: Persuading a spouse to change is easier said than done, and you’ve probably already tried. All we can say is, don’t give up. This is important.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: I’m divorced and have quite a bit of money. Several years ago I was involved with a guy who, once he learned of my wealth, used me as his personal ATM. Recently I started seeing someone new, and I think I could get serious about him. Given past experience, I’m thinking it might be better not to tell him about my money. Would that be ethical, or is there a point at which I have to speak up?

Answer: If you’re becoming seriously involved with this man, you need to tell him. After all, you’d expect him to be forthcoming about his having five kids or having been addicted to painkillers, right? Well, he surely expects you to trust him with comparably important information, and justifiably so. Moreover, if you end up in a committed relationship, your resources are going to play a major role in your life together. Hence you need to be certain they don’t present a problem. This means confirming not only that he’s more honorable than your last guy, but also that he’s not threatened by your wealth. Keeping mum prevents you from getting a true assessment of your partner.

We understand that being exploited by Mr. Wrong has left you leery of revealing your resources. But believe us, the problem in that situation was his character, not your money. Your judgment surely has improved by virtue of that experience, and there are much better men around than that guy. We hope the man you’re seeing now is one of them. But you won’t know until you tell him about your wealth and see what effect it has on him and on your relationship.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: When my grandmother died, she left most of her beautiful antiques to me. Now Mom wants me to share these with her sister’s two daughters. But neither of my cousins had anything to do with my grandmother for at least 10 years before her death, because my aunt and my grandmother were estranged. Mom says I need to do this to keep peace in the family. Must I? I know my cousins will just sell everything I give them.

Answer: An admirable goal, peace in the family, and you’re certainly obligated to take your mother’s request seriously. What you’re not obligated to do, however, is to suspend your own judgment of the reasonableness – or likely effectiveness – of what she’s proposing. And you should certainly take into account what your grandmother would have thought of the deal. It’s one thing if your mother is trying to make up for what was your grandmother’s unfair treatment of your aunt, say, and another if your mother is simply succumbing to her sister’s and nieces’ whining or bullying.

Then too, nothing says you can’t meet your mother’s request part way. For example, you might give each of your cousins just a single antique – ones you believe they might actually enjoy keeping. Another possibility: Specify in your will that some of the antiques go to your cousins or their children, thus ensuring that their “line” ultimately shares in these lovely mementos of your grandmother’s life. Finally, you wouldn’t be wrong to discuss with your mother whether there aren’t some things she inherited from your grandmother that could serve the same diplomatic purpose with her sister’s family as the antiques she’s asked you to part with.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: I’m a research assistant at a large consulting firm. Recently I noticed a significant error in a report prepared by a co-worker who’s always acting superior to me. It’s not my job to proof this report, so I’ve said nothing. The report’s about to go out, and I hope Julie gets in trouble. My friends are appalled, but I don’t think I owe it to this woman to bail her out. Am I right?

Answer: When it comes to having to save (or not save) a colleague from a trip to the woodshed, you ordinarily have a bit of leeway. The problem in this situation is that your silence punishes one of two innocent bystanders: the company you work for or its client. If the client discovers the error, it may revise its opinion of your employer and take its business elsewhere. And if the client doesn’t notice, it could be harmed by fallout from the mistake.

While it may not be your job to proof the report, you still have an obligation as an employee to speak up when you see something’s wrong. If you worked in an operating room and Julie were about to amputate the wrong leg, would you remain silent? Just because the consequences in your situation are less obvious doesn’t make them any less real.

One way or another you must notify the project manager of the error before the report goes out. So tell the manager and become a candidate for Employee of the Month, tell the whole office and embarrass your nemesis, or alert Julie to the problem and hope her attitude toward you changes - whatever you like, as long as it gets the error corrected.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: For five years I worked for my sister’s husband Jeff at the market research firm he owns. A year after I quit, I started a research firm of my own. I’ve abided by the terms of my contract with Jeff, but my whole family is mad at me because now I’m competing with Jeff for business. Are they right? Just because he once gave me a job, am I obligated to get this guy’s approval for every move I make?

Answer: That depends. If Jeff did you a favor by hiring you - if you got the job because you’re family - then competing with him now is an act of betrayal. In accepting a favor of that magnitude, you incurred an obligation to treat Jeff as more than an employer with whom your relationship was arm’s length. Of course he has no right to oversee your career, but he has good reason to expect you not to start a competing enterprise.

On the other hand, if Jeff hired you simply because he valued you as an employee, he’s on thin ice insisting you have obligations that extend beyond the employment contract you signed. Had he expected you to never compete with him, he should have specified that in the contract. In short, if your hiring was strictly business and you’re playing by the rules Jeff spelled out, his outrage is unwarranted.

So what was it, personal or business? Therein lies one answer to your question. Either way, though, you’ve shown a remarkable lack of family loyalty in starting a business aimed at taking customers from your brother-in-law and bread off your sister’s family’s table. Any way you slice it, that’s a hostile act.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: My mother, a widow in her early sixties, works in the administrative offices of a big conservation organization. While her pay is okay, she makes very large contributions to the nonprofit she works for. In return, Mom is duly recognized. But in the meantime she has only a small nest egg, and it’s not getting any bigger. Aren’t the development people where she works, who understand that her means are limited, wrong to solicit and accept so much of her money?

Answer: Absolutely. Soliciting money from someone when you know they can’t afford it is wrong. Period. It makes no difference whether you’re a snake-oil salesman peddling an overpriced piece of Florida swampland or a fund raiser for an environmental organization trying to preserve the same swamp. When you know that the deal you’re pushing runs counter to the interests of the person you’re pushing it on, you’re behaving unethically.

But as dishonorably as the development staff is acting, the buck stops with your mother. She’s the one making the decision to give. And just because her money is going to a good cause doesn’t change the fact that she’s failing to adequately save for retirement. By allocating her income in this way, she’s not being fair to the relatives who may one day be called upon to bail her out.

So unless you or another relative is prepared to supplement her nest egg, you should talk candidly with her about the potential long-term effects of such generosity. Emphasize that while you understand her concern for the future of the planet, you also want to make sure she’s paying attention to the future of her finances.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: I hate to say it, but my son-in-law is no good. Three nights a week he goes out with his buddies, leaving Melissa at home with their toddler. Recently, they asked my husband and me to help them with the down payment on a house. While we would like to help our daughter, we’re sure her marriage will end in divorce, and we would hate to see our hard-earned cash winding up in Josh’s pocket. What should we do?

Our answer: Leave your checkbook in the drawer.

While sabotaging your daughter’s marriage would of course be wrong, being realistic about the likelihood that it will succeed is not. If there is a good chance that this marriage is not going to last, pouring your money into the couple’s joint assets is a bad idea. Not only do you risk having made a very large gift to your selfish son-in-law, but whatever you give them now means you’ll have that much less available with which to assist Melissa should she and Josh split up.

More generally, while helping an adult child with the down payment on a home is a wonderful thing to do, it’s not always the right thing, and it’s by no means an obligation of parenthood. Moreover, under no circumstances are you obligated to give money to a son-in-law you don’t like, especially one whose character concerns you. Since Melissa wants to make this large investment with Josh, that is a decision you must honor. But it is not one you’re required to bankroll. We only hope your daughter’s not imagining that, though having a baby hasn’t kept her husband home at night, having a mortgage will.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.