I may regret starting this thread, but I am truly curious about how you all handle this situation, i.e. what's your tipping point (tipping as in tipping over to the other side, not compensation for providing service)? I start with the premise that when a group of friends dines together, there is a certain point where the disparity among how much various guests ate and drank makes splitting the bill evenly unfair. The question is, where is that point?
Exhibit A: Last week I dined with a group of 10 at a casual, not very expensive restaurant. We ordered a number of dishes to share plus individual entrees. Multiple bottles of wine were also consumed; usually I can drink wine with the best of them but on this night I chose not to indulge. One other friend wasn't drinking either. Bill came, and someone added the tip and then divided by 10 and said it was $66 each. I did some quick math and figured my share, including my relatively low-priced entree and a generous allocation for the shared dishes plus tax and tip was more like $40. I waited a moment to see if the other non-drinker would say something, or if someone else would say "you know, maybe the two who didn't have any wine should pay a little less" [a role I have taken more than once in the past], and when neither of those things happened, I paid my $66 and moved on with the evening. Thinking about it later, on the one hand, it was only $26, which hardly broke my budget. On the other hand, I did pay about 60% more than my "fair share."
Exhibit B: A few weeks earlier, at a more upscale restaurant with a large and interesting wine list, dining with two other friends. I wanted white wine, so I had two glasses in the $10 range. Other two ordered a bottle of red that I wasn't familiar with plus a couple extra glasses after the bottle was gone. Apps and entrees ordered all around. Bill came and I saw that the bottle of wine was $160. Friend then divided the bill by 3, but I objected since I hadn't had any more than a small taste of the expensive wine, and he quickly agreed and recalculated our shares. I felt of twinge of "ugh, am I being a cheapskate?" but I recovered pretty quickly, figuring that paying for wine I didn't order or drink would have added about $60 to my tab, and that was more than I was willing to swallow, so to speak, in the name of not making waves.
So after those very long winded stories, back to my original question - what's your tipping point? Assuming you're not from the school of "life is too short - I split the bill evenly no matter what," at one point do you feel compelled to say something?