No Zimmerman was under immediate threat of death or great bodily harm. Cobb and Dutton were not.  That is a wholly invalid comparison.  The kids as far as I know are not teenagers, but even if they are and even if it's legal it means Cobb's excuse that he was patrolling because of vandals is irrational. You don't leave kids alone at the target of vandalism in order to patrol town and follow other people home.  you're clearly misinterpreting the meaning between situation and principle.