I (and siblings) were regularly hit as a child not spanked hit, with hand, fist, belt, wooden spoon, fly swatter,etc. It didn't screw me up but I always knew it was wrong. I am the only one of my siblings who spanks, one swat open hand on the butt pants up. Now my kids are teens/adult if my son were to get "rough" I'd beat the hell out of him and he knows this which is why he likely won't try it.
SO when I first met him disciplined in private I was pretty sure it was a belt or bare assed, an put the house rule in place, if you hit with anything but your hand I call the cops. It was what he knew and he stopped all punishment is in front of everyone, time outs (I will and have put my 17 now 18 yr old in timeout she needed a moment to chill), a swat, grounding, loss of privileges and we do a lot less punishing because they all know what happens but we blended parents have our asses covered their are witnesses.
I pushed SO to do something about the abuse his children were suffering at BM, regular beatings (daily) with a belt on a 60lb 7 yr old hell No! SO warned her to make her dad stop, she told him to F off grandpa did it again SO got an RO. I'd step in in public with my family, and friends. Sometimes parents lose their cool and do something they wouldn't normally I'm not going to be rough about confronting unless a child is in immediate danger then I am and I'm calling the police. Otherwise I might make a joke or calming comment when I see a really frustrated parent at "that point"

This is slightly different but I was at a portrait studio and a woman was TOTAlLY igniting her three t
Year old child punching, pinching and hitting her one year old. I was in the lobby with other parents, watching as the older child assaulted the younger one. Mom did nothing. And even though it was difficult for all the other patrons to watch, no one said a thing but all just looked at each other with disapproving glances.

It ended up that I as called up near where the
Min and her two boys were. I told the mom something like "I'm not sure if you're aware but your oldest son is really hurting your youngest boy" - giving her the benefit of the doubt.

Clearly this was not a new behavior (and quite possibly something he learned at hone) but the mom took the opportunity to lash out at me instead, rather than addressing the problem. It was a response like, "I'm sorry you're a perfect mom and don't have to deal with this"

Fact was, that's a disgusting mom.

You did the right thing and I hope whoever knows who she is does actually call on her.

I have stepped up in a grocery store and told a man that if I saw him hit his child again I was going to kick him in the balls. The kid was less than 2 and he was just smacking him upside the head, hard, and then when he fussed the man would do it again. I told the manager what was going on as well, they called the police. I don't know what ever happened.

I was spanked with a belt, cord, when I was a kid. I do not spank my kids, sometimes when my OS tries to get an attitude, I will yank him up but I don't hit him. Theres been time that I have "popped" my kids but it was always when they were older. I do not spank my kids, I think its a wasted punishment, I don't think it does anything to help, and it hurts them a lot more if they lose something they like. A child around the age of 2 doesn't understand why they are getting hit, they don't "know" better. I would definitely have said something.

We were walking in a mall parking lot, when a guy started screaming, swearing, and smacking the crap out this poor little boy, probably around 6. He was hitting this kid HARD and the kid was just curling up on the concrete crying. Mom or whoever she was just stood there like a dumb cow.

There were about 4 of us in the parking lot who all starting yelling at this guy to knock it off. He said "It's my kid, I'll punish him however I want." Someone pulled out their phone and called 911. This big badass burly-looking Harley-Davidson dude walked up to assDad and got right in his face and threatened to punch his lights out if touched the boy again. assDad dragged the crying little boy to the car and the family drove off. We got his license plate and gave it to the cop when he showed up.

Now, if I was all by myself, I probably wouldn't say anything directly, so as not to get myself shot or otherwise harmed, but I would call the cops or get a security guard or something.