Well if it was obvious during the game the 4/5th official with a replay screen could advise the Ref straight away. Or even review it a few times while the game goes on and then advise the Ref to card the player if required during a stop in play. I think you've got to be really careful in working out how to do this because you don't want to take it too far. It can't be used for everything, as two different pundits (one ex-defender one ex-striker) see things differently even on slowed down replays. I think unless its absolute the 4/5th replay official should leave it alone.