In regards to the OP- should it be illegal? I think it probably should. But I have no idea how it could be policed. I would imagine it is something that would possibly be used against parents in Family Law Courts? It would be inappropriate to place young kids on the stand in courts to testify against their parents and a tap on the bottom is hardly likely to leave marks that could potentially be photographed for evidence- I would imagine leaving marks and bruises would already come under assault? Its a tricky one, legislation wise. And how many clever kids/teens would be calling the police claiming to have been smacked out of spite? There are so many issues around this, I really don't know if it's possible to put into practice. I was smacked every now and then as a kid and it didn't have any lasting effect on me, but yelling certainly did. When I was younger my dad would shout at me a lot. Even if I had friends over. It was mortifying and I hated it, and I feel it was usually unnecessary.