In my experience what happens is you look at each other confusedly for a moment, wondering who is in the wrong restroom. Then you realise there are no urinals so it’s probably the women’s restroom. Then the man leaves a bit embarrassed. Source: Happened to me at least twice (once the signs were really unclear).
Except for Scheuermilch (scouring cream, literally: scouring milk). That one we can keep. Probably because it has the same nutritional values as cow milk or something… The argument never made any sense whatsoever.