Having a better defined, field-tested procedure is probably a good idea. Roughly A) Confront the aggressor to communicate problems and see if the situation can be resolved. B) Where it can't be resolved, investigate if the aggressor has a pattern of such behaviour, or if there are individuals in a position to be more persuasive that could help. C) If the behavior continues, institute bans, document incidents. D) Where bans are insufficient and repeated warnings have been ignored, escalate to involve relevant law enforcement agencies.