Valid point, DE. But without the plates, how often do we see 20 cars in a knot where they can't avoid one another? In an unrestricted scenario, the faster cars can get away from the rest. The slower cars drift backward through the field. Ususally no more than half a dozen guys find themselves in a situation where they have to avoid a given car. That gives each of those half dozen guys that much more space to maneuver, brake, whatever needs to happen. There's that much less likelihood of being tapped from behind in the first place.
I certainly understand the physics of the situation you describe, and can't disagree with the thinking that went into stopping the practice of racing to the yellow. I just think that a driver, any driver, has a much better chance of missing another car if he has four other drivers around him than he does with thirty-four others around him all travelling at the same speed.
