I’m not going to say that all accounts of twelve stroke canings in a school are false, but I am pretty convinced that such a punishment would have either been dangerous enough to exceed any bounds that might conceivably be considered reasonable chastisement, or that the person inflicting the caning inflicted such weak strokes that it couldn’t reasonably be described as a normal school caning (and if you are not willing to do the job properly with the strokes you do inflict, I can’t see how you’d be willing to give that many strokes).