Sports leagues and venues have begun implementing fan codes of conduct to regulate spectator behavior in response to incidents of fan misbehavior. These codes prohibit offensive language, throwing objects, unruly behavior, and outline punishments such as ejection or banning. They were created to protect fans and the business of sports. The document discusses examples of fan misbehavior in various sports leagues and a specific incident where a fan was severely beaten that led the government to propose banning violent fans from future games.