Should parents ask their teens to tell them about kids with dangerous behavior, drugs, weapons? Should they alert authorities or kids' parents? @drpam

Teach. We need to teach our teens that alerting responsible people about dangerous potential is the responsible, safe thing to do.And is not "ratting" on your friends.This is a change to generations of teenage behavior.
Communication. It is important for parents to have an open communication with their kids about potentially dangerous behaviors of others and parents should not be afraid to contact both the other parents and the authorities, especially if you think somebody is in severe danger to hurt themselves or other people.