Sure, but what about a mag fed gun? Are you going to empty the mag to check them all? What we know as rec or comp shooters is different than what they do in movies.
I/you would never point a gun without the intention of destroying the target, and we would be sure of the target and what was beyond it, and we would treat the gun as being loaded with live ammo, so AB violated 3 of the 4 basic firearms rules from our world, but it was assumed that the gun didn't have live rounds, so we're back to where did the live rounds come from and how did they get into the 'Prop"?