I've never understood gender segregation of single-person bathrooms. It happens in restaurants in Japan too. Drives me nuts when the men's room is occupied and the women's room just sits empty. (In the opposite situation, when the women's room is full with a long line waiting, women often just use the men's room. Of course, if a man tried something like that with the women's room, he'd probably be arrested. )

Oh well, just another reason to switch back to JAL after I get SFC.