Dont think this would help, any team recieving one during the game can just "park the bus" untill the player is allowed back on. Theres enough time wasting/control going on without adding more. How much football do we actualy see? I also go to ice hckey where you get the ful 60 minutes per game. I would like the refs to have a marker/flag that they can throw on the ground beside them when getting questioned by players, any player overstepping this mark will then be booked.