Sometimes, literal translations get lost in translation: Although “please take off water on your body” sounds a bit strange, I have a pretty good idea it was supposed to mean, please dry your body after getting out of the water.
I’m not so sure about Number four, though:
After awhile you get used to this kind of English usage, but it makes you wonder when there are all these English teachers and other professors using the facilities, why someone can’t ask to have such signage looked at and edited. I understand that a lot has to do with “saving face” as well as being shy asking a foreigner to check one’s English.
Then again, as a former colleague of mine, Peter Moule used to say, when we talked about such things, “I’m surprised that you are surprised.”