I can remember a girl in a class when I was at school in the late 70s being asked a question by a teacher and she clearly had been day dreaming a bit so replied "fit?" (i.e. "what?"). The teacher got very angry and threw a wooden blackboard cleaner at her head which just missed by a few cm.

I can also remember some kids getting far worse treatment in primary school for slipping into dialect (e.g. one chap who mispronounced something was told by the teacher to look at the blackboard more carefully so he went right up to it and the teacher went behind him and slammed his head into the blackboard).

[Edit: I should have said "loonie" rather than "chap" - a "loon" being a boy, a "loonie" a young boy - similarly "quine" and "quinie" for girls and young girls - aye it's a sair fecht ;-)]