Should my girlfriend do all these things for her friend?

one of my girlfriend's friend is getting marry. so my gf and several of the bride's friends (including her sister) are planning something for the bride to do before the wedding. But the bride wants to go to somewhere warm and not in the states (like cancun). At least that's before the swine flu and stuff. I told my gf not to go, one paying for the bride to a trip that is out of the states is expensive. I mean if the bride is like a best friend then I will encourage it but she is not. Her friend (which is the bride) is very demanding, I mean for her own wedding that is ok. But demanding of her friends, I don't think so. And not to mention, the bride is cheap on the bridemaids' dress too. Those dresses made all the bridemaids look bad. I just don't see the point of spending so much money on other ppl, plus the trip is only one of the several things the bride wants to do. They are throwing her a wedding shower too.