I went to 2 stalls before I realized it wasn't a prank, it was a Sani-Seat ;) I don't know if that was my name for it, or the official name.
And then out of curiosity, i waved the sensor while I was sitting down, and it rotated! ;)
ps. I hadn't slept that night (explains the hair), so maybe i was reaching that stage where "everythings funny"