I note that our cousins in those USA states where CP is used sometimes (frequently?) have a system of consent forms to be signed by parents: I don’t remember anything of the kind from when I was young, and I guess you don’t too. So maybe that might provide a bit of monitoring. I believe that they also have rules about witnesses. Of course, we had punishment books, but I don’t think that witnesses were required; and the classroom punishments which were extremely common in those days didn’t go down in the book at all.
And, actually, I think that the attitude of parents is incredibly important. If anyone is going to care for a child then a parent will; that’s built into the biology.