Dear Etiquetteer: The topic of split checks in a group dining setting came up, and we would love to hear you weigh in on this. My friend was stuck with a $150 extra bill because her group of 35 friends couldn't, or wouldn't, calculate their fair share. As a generous, and prosperous, friend, she simply covered the difference. As often as you dine with friends, large or small groups, you must have the perfect solution, if one exists.
You raise a sore subject for many people, including Etiquetteer. One always wants to give one's friends, or the People With Whom One Dines, the benefit of the doubt. What's that old saying "Better to assume incompetence than malice," or something like that? This goes only so far when one is left holding the bag for $150, or even less. The issue of a split check becomes more complicated the larger a party is, so much so that there's no Perfect Solution. Etiquetteer does have ways, however, to mitigate disaster.
First and foremost, every split check dinner party should have a leader who can be counted on to be sure that the check is paid in full and that everyone pays their fair share. Usually this is the organizer of the party, but if that person's math skills are less than stellar (like Etiquetteer's), an accountant type in the party should be gracefully drafted to assist.
Second, no one leaves until the check is brought and reviewed! So often this is how trouble begins, and Etiquetteer knows from experience. Etiquetteer himself led a pre-theatre dinner party once. Having to leave early to distribute tickets to other theatregoers, Etiquetteer was horrified to learn that a member of the party was stuck with an outsize portion of the bill because 60% of the guests left before or during the arrival of the check. And even when people leave "what I think I owe" they should overestimate rather than underestimate. Of course Etiquetteer doesn't want to suggest that they deliberately underestimate -- remember the benefit of the doubt -- but repeat occurrences will help you judge.
Third, when dining out in a large party -- say eight or more -- everyone should be prepared to pay a little more than they think they'll owe. Why? The most obvious reason, and one of the most tiresome to Etiquetteer, is debate over the amount of the tip. Many restaurants add a pre-announced percentage to the bill of large parties for a gratuity (and Etiquetteer usually doesn't blame them). When they don't, the personal opinions of diners can legitimately disagree over the quality of service, but it's an awful waste of time, and not very enjoyable. When tipping in large parties, err on the side of overtipping for the sole reason of not spending a lot of time talking about it.
The other is that, for very large parties like the one your friend attended, it can take as long as the dinner to divide the check! The most expedient solution, as the world knows, is to divide the check equally by the number of diners. And, as the world knows, this leads to automatic resentment from those who ordered less (often for budgetary reasons). The most resentment, as Etiquetteer has seen, is usually directed at those of the party who drank more alcohol than others -- not because of their behavior, but because of the cost. Even the best of friends get unhappy if they feel they're subsidizing someone's bottle of wine. Depending on the party, it may be better to divide the bar bill separately from the meal bill.
Fourth, if worse comes to worst, insist on a separate check for yourself and/or the two or three people seated with you. So many restaurants now allow multiple credit cards to pay for one large check. And indeed, Etiquetteer dines semi-annually at a lovely restaurant with a large party, and the waitress automatically brings separate checks for all 20-plus diners.
Etiquetteer's solution for troublemakers, as it is so frequently, is exclusion. If people aren't going to behave with Perfect Propriety, there's no reason to subject yourself to their, in this case, costly behavior. Stop inviting them. This doesn't mean that you need not socialize with them at all, just not in split check situations.
But if this type of situation comes up frequently and always makes you unhappy, the best solution is not to dine out in large parties. When accepting an invitation, confirm that there won't be more than six (or four, or whatever limit you set) in the party.