I've never heard of an "I'm glad I'm not" social, but from your examples from last year, it sounds like it has the potential to turn into a scandal (like what happened at North Dakota
Sorority suspended for "Indian" party). I don't think there's anything wrong with dressing up like a stupid celebutante or dressin up like blue balls, but if anyone is dressing up like Hitler or like a dyke, I hope you all are smart enough not to be posting stuff like that online (facebook, myspace, flickr, etc.)