I'm with carlton, as if you couldn't guess from my previous replies!
If my child, who's now 6, does something spectacularly bad, she will get a wallop across the bottom, or legs (whichever I get to first!). She is, on the whole a polite, reasonably well behaved, well adjusted polite child who clearly knows the boundaries between right and wrong. I can't help but thinking this is because she knows that if she majorly erros, she will be punished.
For generations, children have been brought up with physical punishment as a deterant, and please bear in mind i don't mean beatings here, just smacks and taps, and the majority of those kids have grown up fine. Now we're in a society that's gone all hippy and tree huggy and frown on smackings, and look where we are? A generation of kids who have no moral boundaries.