I do remember reading in the school rules:
“Misbehaviour in toilets will be severely punished”
To be honest in my form we could go weeks without anyone getting the cane, and then it might suddenly be for a petty thing like when a group of quite untroublesome friends of mine got a couple of strokes when the caretaker caught them paying chase on some out-of-bounds grass
I do remember the Deputy Head expostulating at assembly more than once that anybody caught fighting would get six. No doubt implemented but it was never going to be particularly effective. I guess it helped to deter some of us from reacting when we were pushed around by the loutish fringe.
One offence guaranteed to merit the cane was any form of defiance of authority. Caning was very rare in the senior years, but I saw two instances where the perpetrators of apparently minor acts of defiance were summarily given six strokes.