My little brother use to get bullied after school at least once a week by this kid named Gorge Ramos who was 2-3 years older then my Brother Hecky. So everytime he beat my brother he'd come to me crying, lucky for me Gorge lived in the same complex as me, so I'd go to the back alley to find him, confront him and kick his royal ass SNATCH style. It became a routine & the adults placed bets on me. But to answer your question depends on situation and once a person can handle their own no need to get involved and if others try to get involved unfairly you dial 911 because you don't need to build a police record for bad behaviour.
Im_BadBOYS
