I think you’re right about the parent’s role in child issues. I went as an unofficial step-parent to meetings at a child rehabilitation center, and it was clear that most of the parents were in denial/ignorance/defensiveness about being at least as much the source of the problems as the children they had interred there. The psychiatrists generally knew that was what was going on, but didn’t know how to penetrate the parents’ mindsets given the legal situation. So I’d say that a nanny cam isn’t necessary because a good psychiatrist can tell mostly what’s up. Well, the cam might help to create evidence for legal action by a non-abusive family member (e.g. the common case where one parent or stepparent is the main problem but no one can get rid of them, and that sort of person isn’t going to want the camera, and/or will avoid abusing on-camera if they know about it).