Its a difficult one. When I was very young I always walked away when someone hit me and I tended to get bullied until one day I hit the bully back really hard and then he never hit me again. I did notice that kids who hit back did not seem to get picked on whilst those who walked away did ! It does depend on the nature of the child being hit. Some will think nothing of hitting back - and yet others find they just can't - so what they are told by a parent will just be ignored anyway.