Dr. Kevorkian wanted to help his victims too. By killing them.
Of course, there is a method to that madness. In the case of Dr. Kevorkian, he was ending terminal patients' suffering. And the same principle applies to the "save the kids" argument. In essence, if you get a kid before the worse villains do, you can prevent the said villains from doing their villain things.
I only know this stuff because it was done to me. The subtle jump scares I got as a kid continue to save my ass all the time. But it wasn't really abused. Plus, for that theory to even work, the person doing the shadowing needs to be meaner than everyone else. It also doesn't prevent people from hurting themselves.