What they are saying is that if you see someone stopped at an intersection you can't tell if they are stopped, causing you to slam on your breaks and someone rear ending you..
This is the STUPIDEST thing I've ever heard.. You should have full control of your vehicle at all times, if you panic and lock your brakes up it is noones fault but your own.. Same goes for animals, etc. "I saw a dog on the side of the road, I couldn't tell if it would run into the road or not so I locked my brakes up..." BULLSHIT! Some people just shouldn't drive.
