To prevent players loosing their temper during a game, they should imply stricter rules like suspending them for the season. By doing this a player would think about the consequences before they start a fight during a game. Doing this a player will most likely think about their team before making a stupid decision and upsetting his team. High fines may also work but in my opinion it would not make a difference because I do not see money as an obstacle that can prevent a situation like the one in the picture.
Mr WordPress on Hello world!