If one is an artist (no corporate / office job) one can wear whatever they like, whenever, right? I happen to know many artists and none is imaginative or daring, they all dress like accountants (and their art is equally boring and proper). People have become very conservative imho. This is why suddenly Gaga is "hot" and a novelty, because no one else is doing it. No one is daring enough. I just wish those who can do it to actually do it, not necessarily with cross dressing, but with being daring and avant-garde. Crossing the line between male female and reinventing one's appearance & identity is a step towards this.
And I highly believe that life imitates art, if artists do it, the world changes.
I wonder what would woman do if suddenly we were told that we are not allowed to wear pants anymore... Wearing trousers was an important symbol for women's rights wasn't it? This subject has social and political and philosophical roots, imho saying that "Oh no! Men should stick to men's wear" is very narrow minded and borderline homophobic.