On the question of fairness, there’s still the general point of what to do when fairness and effectiveness are in conflict, as they might be on occasion. But as far as my primary school was concerned, fairness wasn’t an issue as far as I remember. Certainly there was differential punishment for boys and girls — girls were never caned, and only slippered very occasionally — but that would only have caused probems if a boy and a girl had been caught for the same offence and given different punishments. And that never happened — boys and girls were different species and never misbehaved together