I saw those in action on imgur a week or so ago. When you flick the switch on the door to occupied to automatically frosts the glass so no one can see in or out. (Or at least that's what the person inside thinks....
). The comment that stuck with me, though, was someone saying that you know these toilets had to be somewhere like Japan because the glass would have been all smashed or tagged with graffiti if it was in the US (although I'd extend that to Canada as well). That comment has stuck with me and is another sad indictment on the negatives of the culture we have. This is why we can't have nice things.