I see a serious potential problem with the idea of reviewing for penalties. I would bet that, on a fairly high percentage of plays, there is something that could be called. For that reason, a coach could cherry pick a few potentially game changing plays each game. The reviewing official would have to decide whether or not to call tacky-tack penalties that are often let go by the refs. Since the play would be there for all to see, the reviewing official would be under a lot of pressure to make a call even in marginal cases. This would cause lots of big plays to be called back. I am all for getting calls right, but this would be a very biased correction mechanism.
