First of all I am surprised no one else commented or offerd up an opinion. If people are interested I can post plays, either in video or just text, but if no one cares I won't worry about it.
I used this play because it perfectly illustrates a key issue regarding blocks in the back. I've looked at this video over and over, and I can't tell if it was illgal or not. But if all you see is the end, it sure looks bad. You see a guy driving a defender away from the ball with a puch in the back. To everyone there, including the coaches with the camera and probably Johnny's grandma in the 25th row, it looks like an illegal block. But the clock started legally and if contact was never lost, this is quite legal.
I've seen a lot of officials see the end of a block without seeing the initial contact and go with a flag. I'm sure I've done it myself over the years because it's easy to do and no one wants to think we have everyone there thinking we missed something so obvious, but the little details of calling the game are trickier than that.