i think it was already banned in schools which is where the confusion comes in.
I knew a kid when i was growing up that got smacked by his parents almost constantly for the most tenuous of reasons. He didn't change his behaviour at all, he just got slapped more
I always found that my kids know exactly when to behave purely by the tone of my voice, i don't even need to raise my voice. The point being they already know that they are doing something they shouldn't, its called knowing right from wrong and that is the important lesson that a parent teaches. After that, nothing else is needed.