While I can't really condone the use of the cane, slipper, whatever as a form of physical punishment it certainly acted as a deterrent when in my schooldays. The added benefit in those days was that we did not have the compensation culture that is so prevalent these days. My old dad would never have dreamed of fronting up at the school protesting on my behalf. More likely he would have told me to stand on my own two feet.
I do realise that times do change and at risk of sounding like my parents, quite often they don't change for the better.
Or, probably as in the case of most around our generation, given you extra punishment for daring to complain you'd been hard done by. It's quite ridiculous these days.