Can that not have the same effect as smacking though in that the kids aren't behaving because they are being engaged with but just because they are scared of being embarrassed in front of their peers ? and that can have just as lasting an impact in terms of perception and willingness to comply with authority in later life .If they told me to "**** off" I'd just give them more work. If they didn't do that, I'd just repeatedly embarrass them in front of the class and keep doing it. The easiest way to engage with a kid is on their level, and once you do that you actually have a lot more power over them as they realise that they don't have anything on you that they can do better than you. If I'd hit them it wouldn't have changed a thing, as I saw with some other teachers.
When I was at school not that long ago there where two teachers who everybody knew would embarrass you in front of your whole class/year group / school . One of them was my maths teacher whilst I was in year 11 . He used to bring year 8 and 9 pupils who had been misbehaving and completely embarrass them in front of us . At the time we all though it was funny but thinking back that was effectively involving us in the punishment of another pupil and I dont think that is right either . Punishment should be between the person who has done the wrongdoing and the source of authority it should not be a spectator sport .It didn't really work either because many of the kids who he would bring and embarrass still ended up being suspended from school or in an isolated learning environment .
Yes you aren't using your physical superior strength to inflict pain on another pupil but you are using your superior intelligence and cognitive ability to inflict embarrassment .