My wife has thrown me a surprise birthday. I know about there's about 15 people going.
I haven't been able to workout the location yet. Yet, I know my wife, she's going to expect everyone to pay for themselves.
If I was going to an invited meal, I would be 50/50 about paying or not. If they pay, great if not, no problem.
My wife is cluleless with money, she won't have anything prepared. Not sure if I should be prepared to pay for everyone's meal or not?
I don't think there's a consensus etiquette-wise. It's all very case-by-case I always assume "dutch" (everybody pays their way), but not all do, so this should be made clear. I can see certain times where it could be different. For instance, my father-in-law loved a particular fine dining restaurant, and it was tradition for him to have his birthday dinner there. When we were invited for his birthday dinner, it was sort of understood that he would be paying (even if it was his birthday).
And then there are the usual group dining problems, like how to split the bill. Does each party pay for what they bought? Split evenly? I demand the former. If I bought the chicken, no way am I going to pay as much as the guy who bought the filet.
Odd though, that when it comes to kids' birthdays, the host parent always pays the whole bill.