Call me a cop-lover, but I thought the same thing when I saw the video. "Distraction blow" indeed, because often when someone lies prone it is to HIDE drugs or weapons. I've seen way too many COPS episodes where people stopped their car, waited until the police officer got out, and then drove off, too many perps who put up their hands in the air, wait for the officer to approach, then pull a gun out of their waistband, who turn around as if to prostrate themselves, in reality dropping their baggie(s) on the ground. If I;ve been chasing a known gang member for ten, thirty minutes, who may or may not be armed, I'm sure as hell not going to simply walk up to him to secure the arrest without backup or a "distraction blow." If he'd tased him we'd all be "oh, ok", but kick him in the head and it's a big bruhaha..
Take, for example, a criminal who decides to open fire on officers attempting to give him medical assistance after a crash..