I have a few friends who have told me that they smack their children as a form of discipline and yet I have never witnessed it eventhough I have witnessed their children misbehaving. One particular Mum I know often looks very tense when her children are misbehaving as if she can't administer her choice of discipline.
This proves to be very trying as the children seem to know that she will not discipline and run riot. Very occasionaly there is a threat of 'telling your father and we know what he will do' which gets a short lived response.
It's as if they are not comfortable smacking in public. If you do use smacking do you feel inhibited when out and about? I can't recall seeing a child been hit in recent years, not for a long while.