I agree with y'all. By the way, my two events were on the same evening. I do generally apply the fool me twice shame on me principle. Surfmom- that is great that you do that. I generally make note of the shortage and also just toss a few extra bills on the table to cover it for the wait staff.

For me it only depends on my own situation. I wouldn't do this traveling if I weren't in good $ shape, so if someone I travel with is not in good $ shape, I pay and forget it.

Or don't travel with them if it bothers you.

MaliaBrody, Ah, now I see. You just don't seem to like the hassle of asking for the money back.

Instead of doing an on-line thing; take a moment during the day to say, (before the eating or drinking commences, "hey, we're all going to dinner. Does anyone need to go the ATM?" and add with a smile, "Last chance."
Your part will be done.

MaliaBrody - since it's not the "borrowing" that bothers you and they're not taking advantage of you, I would simply tell everyone that while you don't mind helping out, it just gets too difficult to keep track of it all during the trip, so you're not going to do it this time.

They'll probably try it at some point saying "oh, but it would just be me", etc., but just stand your ground and say "but if I make the exception for you, then I have to for everyone and that's what I'm trying to avoid."

A different option might be to tell each person when you're alone that "while I don't mind loaning YOU money, I've found I'm doing it a lot for everyone so I'm not going to do any loaning this trip. It's not YOU, it's all the others borrowing, but I can't tell them no and then turn around and loan to you."