As far as I know, hands on was commonplace in Infants & at least the first 2 years of Juniors from the 50’s through to the 80’s. There were 3 good practical reasons for this being the preferred modus operandi:
1) CONTINUITY
Teachers were fond of saying “You wouldn’t do that in front of Mummy/in your own living room”, so what better way to illustrate this than doing what most Mums did & smack your bottom?