Also, I would like to add that laying down is also a strategy for the less "armoured" or bashier teams. Why stand up a player to risk him getting hurt twice if he would have a high chance at failure at any action he takes if he takes an action(roll of the die)? I would preserve him for the next drive. By twice, I do mean an action and getting fouled. Most opponent's will foul the important players to try and gain an advantage in future drives.
If you stand, they can still knock you down (and with higher tv teams, this usually means more risk of injury (mb/piling on/claw)). If you stay on the ground, ONE foul and usually only one roll on the injury table instead of potentially two...
If a player holds on to the ball about to score, but won't until the last turn, if well defended, it would be pointless to put my guys in the fire even if I haven't suffered any casualties. However, this is extremely rare. But in the higher leagues, this becomes a bit more common. This rule could be tough to "defend" in my opinion for something like this.