事故 is a different story. That boy was 故意的.

Please don't misreading my post. I never said it is OK to punish a kid who hurt others by mistake. (Actually, depends on how serious it is, even mistake should have its consequence.)

Besides, Claire mom did not really hurt the boy, did she? It is more like a spanking. (Sounded like the boy got much less hurt than Claire.)

As a matter of fact, if my child did something like that boy did, I am OK for the other parent to punish him; on the premise that the other parent did not really hurt him (i.e., breaking his rib or lung is not OK).