Morgan, for a thought balloon that is a brilliant idea.
The drama would be awesome. The coach and the public find out that a player has been cited. If the coach thinks the ump has overreacted, they leave the player on, safe in the knowledge that the MRP will throw out the charge. If the coach is at all scared, the pull the player and live with the disadvantage. All the while, the big screen could show a picture of the player with a countdown clock showing the time remaining until they need to be pulled or face the consequences. Given that the spectators need to be kept in the loop, the incident would have to be played a few times on the big screen
The key point is that it greatly increases the drama, and given that the AFL hate drama, they won't like it. Unless they realise that much as we all love a good clean game of footy, we also love drama, and they will make more money from the drama.