A woman with a small baby in a pram was struggling to deal with her 2/3 year old's behaviour. He was crying and shouting and rocking the table with their drinks on. She picked up his juice carton and hit him on the side of his head with it. He ran out onto the pavement crying and she followed with the pram. I didn't see what happened next as I was busy with my own children, but as we left the cafe, she twisted or pinched his hand.
At the time I didn't know what to do to help them both, so did nothing, but thinking about it later, I wished I'd said 'you seem to be having a hard time, can I help?' WWYD?