I can think of many an example throughout both my junior and secondary education. Known troublemakers were often punished on the flimsiest of evidence.
However a story comes to mind as told by a girl educated in a Sheffield comprehensive in the 1970s. She was repeatedly singled out by one particular teacher to be sent to the Headmaster, the consequences of which would normally have been the strap on the hand.
However the Head was perceptive, and bearing in mind the girls’ good behaviour record with other teachers, he only warned her about her future conduct. This happened several times in a term until eventually, and somewhat apologetically, the Headmaster did strap her “in fairness to others”. You might suspect that he would have “gone easy” on her, but this does not seem to have been the case.