No, because it's not as simple as you think it is. Having reffed, your mind is conditioned to red/green, right/left and connected to the scorers table, the scoreboard, and the ankles of the wrestlers to insure you have the right wrestler scoring. It might seem cool to the fan, but changing out colors every match at a tournament would be an absolute nightmare. People would be yelling all day long that the score was wrong and coaches would need 17 bricks to get things right.