I agree with everyone else: Prudie totally dropped the ball on this one. Every bridesmaid wears a costume, of sorts, and compared to some bridesmaids' outfits I've seen (a purple dress with silver shoulderpads comes to mind) she could be getting off easy. I'd also like to add, the "say you'll be happy to attend, just not be part of the wedding party" advice is particularly awful. If the LW is horrified at the thought of standing in the middle of a group of friends who are all in costumes, how much worse will it be at the wedding and reception when she's convinced everyone in the wedding party is thinking of her as The One Who Thinks She's Too Dignified For Us?