I have serious doubts if those girls you mentioned were actually caned either on hands or bottom. They were just probably given a stern lecture. Sometimes the passage of time can distort the facts.
In all likelihood there was probably hardly any corporal punishment of girls at your school except maybe the odd smack or two from the gym mistress. These smacks may have been given in a somewhat joking manner and would not really be considered corporal punishment. Sometimes girls can exaggerate punishments just to big note themselves.
Although our senior gym mistress was very strict, she also joked about quite a lot and consequently was very popular.
