Just to continue on these theme a bit. I'm gonna cite an example of slapping/smacking I had described by my dad last time I was home. He's a photographer so he takes pictures of kids quite regularly and is also fundamentally against slapping.
So anyway he has this kid in for a portrait and the kids a bit cranky and hence not behaving themselves so the father says to the kid to behave and smile for the camera or the kid'll get a smack. My dad immediately pulled him up on it and quite bluntly told him that under no circumstances was the father to hit that child under his roof.
So get to my point. The kid had a fair warning, the father was calm and collected and obviously the right thing to do was for the kid to behave. Taking this into account, how is it ok for the father to slap the child?
Well, for a start, my parents would never have warned us that we were going to get a smack in front of people. That would have been humiliating for us. In a situation like that Dad would have taken me to one side, said "please sit still and smile for the camera", given me another chance and if I was still misbehaving taken me aside again "if you don't sit and behave I will spank you when we get home" and I knew that it was behave or he would follow through and I would get spanked when I got home.