Kansas City fans cheer as Chiefs quarterback Matt Cassel lay injured

They are in violation of Rule 1 of The Official Rules Of BOOing

Rule 1-An Injured Player- Never BOO an injured player-Completely unacceptable to BOO or celebrate an injury to a player-remember they are playing a game and have a life to live and an injury could affect that. Only a cold-hearted, ignorant and mean spirited person would do this.