If it is truly a beating, I would wonder what was up and if I should step in. Was the child bloody, were there broken bones or other injuries?
However, I think some people call a “spanking” (a swat on the butt to make a point) a “beating” as if the two were in the same class. I don’t think they are, and if I see a child who has been grossly misbehaving get a spankin’, I’m relieved that the parent is doing something about it.
In my job at the grocery store, I’d see children licking the grocery conveyor belt (eww!) or rolling around on the floor so no one could get past, or screaming like a banshee. And the parents, who believed violence was wrong, would try to reason with their two-year-olds, saying, “Tommy, please stop” or “Tommy, I don’t like it when you do that,” or “Tommy, that’s not nice” over and over and it does NOTHING. The thing is, you don’t need to beat them to make them stop – a simple spanking will do. You can’t reason with them until they understand what reason is.