Adult slapping someone else's child's hand at playground = teaching child how to be a bully at the playground; next thing the child will be doing is shoving a smaller child. What if you saw some stranger woman slapping YOUR child? The adult who needs to rely on slapping a child rather than with intelligent verbal communication (even if it's just three words) is the one with the midget brains. Putting your arm across the slide as the wayward kid climbs up it will stop him in his tracks. Give him a good "look" and you won't even have to say a simple "no" for him to get the message to get back down.