I guess modern analytical process includes this as well. If a referee is known for giving out excessive red cards, I guess these bettors may stay away rather than believing into a team's strength and weakness.
The player that is giving red cards fouled to the extent that the player deserves red card. Any referee can give a player red card. It is worth knowing that a referee can give any player red card at any time in a way no one can know the next match that red card would be given to a player.