I remember this video, and it just points up something I've said for years (while I'm not an NRA Instructor, I did instruct pistol marksmanship for my Unit in the Army, and safety was front-and-center):
[In My Opinion], No one has ever been shot accidentally with a loaded firearm. People shoot themselves accidentally with firearms they think are unloaded, and thereby feel safe in letting their guard down. Every gun, all the time, under all circumstances, should be treated as if it were loaded. I used to say that you should imagine there's an endless laser beam coming out of the barrel and that, should it touch anyone in any way, that person would die. The imaginary laser beam should never, ever be allowed to cross the plane of anyone. If you have to turn and it would bring the direction of the barrel across someone, you had to go up and over them so as not to cross their plane.
Further, if someone had the courtesy to clear their weapon in front of you before handing it to you for examination, it's your responsibility to double check them and clear it again! This is not meant as an insult, or because you don't trust the other guy...it's just meant to be one more layer in a continuing effort to keep both your asses safe!
That's all I got...