But it's even worse than that. The dude doesn't even have to be in a dress. It could be any man who at that moment decides for whatever reason to enter a women's rest room.
And whatever that reason is, it will not be a good one.
This is not just uncomfortable, it's downright scary. If my little niece enters a women's rest room, and a man soon follows her, I (a man) would be in there PDQ, carrying something heavy. No way would that turn out good.