LO 2 (1.5) got hit in her face with a truck by an older boy (4 or 5) at story time. She was working on a puzzle when he ran up and whacked her with a truck....kids are crazy! I was consoling her so I didn't say anything but a grandma sitting near us told him that hitting isn't nice and you should say sorry.
How do you react? Do you just wait for the other kid's parent to discipline or do you say a few things, etc?