It's always been my understanding that, unless there is a prior agreement by all parties, if you invite people out to dinner/drinks/etc to celebrate an event, the host(ess) of the event pays.
My 20-year-old cousin (the youngest of the now-adult cousins; the last two are 2 and almost 5) is moving away to a new city to find a job and start school in the fall. Note that this cousin is my cousin June's youngest sister, and this particular branch of the family has taken on June's custom of "celebrating" some event (birthdays, anniversaries, whatever) at a restaurant and having everyone pay their own way. Which is just not cool.
They're celebrating my younger cousin's going-away at some sushi joint next weekend. I'm not particularly fond of sushi and I have no real desire to see or speak to my cousin June anymore after the Christmas debacle, so I'm not going. Plus, if I'm invited to a celebration, I expect not to pay my own way.
At my friends' and my "girls' nights," we each pay our own way, but we've decided by mutual agreement to always split the tab evenly, no matter who has what, just to minimize confusion and make it easier on everyone mathematically. We take the tax on the meal, double it to get the tip, then round up to a number that is evenly divisible (or close enough) by the number of diners attending. My family even did this at lunch yesterday (mostly because there were 7 of us and no one wanted to sit there and figure out who owed what).
But I know no such thing is going to happen at this upcoming event. Someone in that branch of the family is going to shortchange the rest of the attendees and make everyone else cough up the difference (it's happened before), and since my cousin June and her husband are raging alcoholics, it's quite possible that I'd be throwing in for their gigantic bar tab when all I had was a beer or a shot or two of sake. No flippin' way is this going to happen on my dime.
What bothers me the most is that this branch of the family is always bragging about their money and material possessions (I guess my cousin June had to learn it somewhere). If they have so much money to throw around, why do I (or any other member of the family) have to finance part of this get-together? I'd rather spend the time with my friends, with whom I know I'll enjoy the company, I won't be subjected to the brat-tacular antics of cousin June's offspring, and I won't end up paying part of a huge bar tab for a raging alcoholic because we limit ourselves to one or two alcoholic drinks at most at our gatherings (we're big girls; we know how to keep our impulses under control).
I know it was my cousin June who chose the venue, too, because she happens to love sushi. While I like one or two sushi offerings, it's not one of my favorite foods (because I don't like seafood much), and most of my family isn't partial to sushi either. I don't think a lot of us are going to be in attendance, because we don't much feel like paying our own way at what is ostensibly a party. If I invite people out to eat, I never expect them to pick up the tab. I paid the entire tab for my mom's last birthday dinner, all $200 of it, because I made the invitation. Therefore it was my responsibility to pick up the tab.
Why do some people never learn the difference between "a party" and "a night out on everyone else's dime"?