I was at walmart the other day
This is the first and foremost issue, methinks...
But it isn't legal to beat a child in most places. Are you sure she was actually hitting him? Strange as it sounds, maybe you were mistaken. If not, then she simply got away with it by virtue of not getting caught. People ignored it, no one said anything. Same thing happens with thieves, murderers, arsonists, jaywalkers, etc. on occasion, but that doesn't make it legal. :o