Thanks so much for the replies! I'm leaning towards not buying for them. The event isn't at my house and we've never done your typical "everybody sit down and open gifts" thing before so I don't think it will be glaringly obvious if I don't buy for them. Another thing is that you don't always know which kids are going to be there every year. So I would run the risk of buying for everyone and half of them not turning up because of the distance their families have to travel.
I don't mind being generous but it is hard to buy for kids who are not appreciative and already have more than they know what to do with. I can't afford to buy them all new ipad4's!!!
Also, Brit, the age thing is sort of my issue too! I am 28 but I got accustomed to being considered too young to be expected to buy gifts and I've never been able to figure out when exactly that expectation changes! Mostly because I don't have kids and I've always seen that as the turning point between childhood and adulthood! I don't want to grow up!
-C