Like I say Lauren I think when it comes to parenting everyone has to make their own choices about smacking! I just found other ways to deal with things and think myself lucky I was able to. I was never smacked as a child either, my mum is really opposed to it and can be quite full in when talking about it.
I used naughty chair and removed their favourite things from their room to let them know I was unhappy with their behaviour. When they were very little I moved them from what ever it was they were doing wrong and said no very firmly, if they repeated it 3-4 times I placed them on the naughty chair.
In fact I have a naughty chair in TIBB dungeons