That can mean a lot of things. But good leaders/parents address the fact that there might be revenge. Understood that you probably can't guarantee 100% that there will not be retribution, but if adults are on top of it and watching for it, it can go a long way. Also, leaders have the ability to change the situation--i.e. keepin the parties away from each other (preferably move the punks who assaulted him to other schools or districts).
I think adults need to be very proactive on shutting this down. We can't hide behind what ifs; we rather have to address them head on.