I think I visibly shuddered when I watched this video (It is safe for work).
Apparently bullets whizzing by you as you train and is quite common at Tactical Response classes. My personal opinion is that I would never do what the photographer did, nor would I shoot with someone standing next to the target. I know I will *never* be skilled enough to guarantee I would not make a mistake. As far as I am concerned even the best shooters can make mistakes or have equipment failures, such as a pistol going full auto.
The counter argument is that the elite military units train with live cross fire, none of the four rules of firearm safety have technically been broken and that if you trust the shooters it is not any less safe than driving a car (I don’t know about this last point, that is just the argument).
UPDATE: James Yeager’s official response can be viewed here.