Good question. I don't know what the rule is, but if they miss a flagrant foul call in live action and let play continue, I guess whatever happens during the play can't be wiped out later. SMU got two points gifted to them by the zebras, and it was a 5 on 4 situation for the Ponies.
I do know they're not allowed to stop play for an injured player until there's a dead ball situation, although I suppose if somebody is lying on the floor spread eagle in the middle of the lane they'd have to do something about stopping play so the injured player doesn't get trampled.