I got smacked as a child and I've never suffered a trauma as a result of it! Although I'm not a parent myself, if I was, I would certainly use this as a way of disciplining my child, although at only two years old, I think that your daughter is a bit young for this. I wouldn't rule it out for when she is older though, as I know so many people who are rude/spoilt/obnoxious, and the common denominator is that their parents took a soft approach. You're the best judge of what is best for your child - just don't let them down!