I can only guess that you were not at school at the time 60’s/70’s otherwise she would know that this was not that strange an occurrence and that corporal punishment was just accepted and un-questioned by pupils and parents most of the time, the cases that went to court were the minority, not the ones that went on every day in most schools of the time.
You are correct when you say there are many authors on the FR site who bear female names and who claim to have feared Mr X’s slipper at school but that is NOT to say they were actually whacked with it.
I don’t doubt that some schoolgirls were whacked by males but, out of a female population of some 30 million, how many claim to have been so dealt with? The figure is minuscule. Now ask the almost identical male population whether or not they were whacked at school by a male – and the figure will be very significant indeed.