When Appropriate vs. Inappropriate Use is Confusing

A rather challenging issue is understanding when a student is conducting digital research for appropriate reasons, vs. inappropriate reasons. I'm thinking of subjects such as drug use or terrorism. A completely sweet and innocent student might just be trying to learn what it is that everyone else is talking about, or may perhaps be leaning towards or being pulled into accepting deviant behavior, or perhaps maybe isn't all that sweet and innocent as everyone thinks. I don't know if teachers or even parents can ever be sure about motivations and influences. It's like the old saying of just hoping you've raised the child right to make good choices.