Ditto (re going to cons in part to get away from that sort of crap).

For that matter, I suspect I'd mind less if someone advertised a party with posters saying something like "you must be wearing a short skirt or kilt" and applied it to everyone, regardless of gender. I still wouldn't get in (I don't own any short skirts, and probably wouldn't take a pair of shorts to Arisia, given the time of year), but it wouldn't feel quite as much like yet another example of het guys making rules to give them lots of conventionally pretty female skin to look at, while not providing eye candy for people who'd rather look at men, or making the men meet any requirements.

Hmmm. "Short skirts or evidence of having showered within the last hour", anyone? (I have a hunch that the guys who organized that party would have trouble getting into a similar party in the outside world.)