Use the in-game Team Designer program at "\games\team data\teamdes.exe" to edit the "referee.dat" file in the "\games\total soccer\sys" directory. A "team" containing the referees will load. You can edit the referees' stats in the same way you usually edit the player skills. The only rating that is relevant is "Keeper Skill". Its value determines how strict a referee is. Setting it to the maximum of "100" means that the referee gives at least three red cards per game. Setting it to the minimum of "1" does the opposite.