international rules no fighting. but where the game originated it does. anyway believe it or not it keeps the game clean (you make a dirty hit that could kill someone you have to answer to the tough guy)
this is very extreme but basically the guy (moore) who gets sucker punched in the back of the head by todd bertuzzi in the meeting before moore did a bad hit on eric lindros who was one of the top players of the league later retired early due to dirty players.