this is one of the reasons why I think a firearms safety course ought to be mandatory. say what you will but all it takes is one numb nuts to ruin a perfectly good day, and there are a lot of numb nuts out there.
It won't help. I've been to ranges where new customers have to watch a video. Folks roll their eyes and harrumph through the whole thing. It doesn't work.
I've seen trained LEO's have ND's. I had a competition shooter (and LEO) crank one off on a busy salesfloor. Another I know had one at home, in which the bullet traveled into his neighbor's house.
A mandatory class won't solve basic irresponsibility.