I'm often concerned that my intrusion will piss off the parent, who will further hurt the child when out of the public eye. :(

I'm a mandated reporter, as a teacher, required by state law to report any/all cases of suspected abuse, anywhere, to authorities. I'm careful, but I have to, or I'm liable -- not only ethically, but legally/professionally. If I thought there were verifiable abuse, I'd have to call someone.