a neighbor once handed me a pistol, it was an HK. I remember it vividly because he handed it to me in a way that he flagged himself. I instinctively dropped the mag and checked the chamber to find that it was loaded to his stifled horror. I was at the range last week and showing another guy my pistol and ensured that he saw no mag in well and that I demonstrated an empty chamber--a process that takes seconds.
safety
and it is very human, when doing a quick repetitive task, and a little distracted, we see what we expect to see and miss the reality.... ....that is why double and triple checks, each person checks, etc is also good practice.... ...not being insecure and get insulted if someone checks for themselves after you had just checked, etc....
I stowed a pistol in the carrying case about to take it home, with a dud round in the chamber, because it was a dud, even my dry fire in a safe area/direction before stowing for the day, didn't catch the mistake.... ....only my son double checking everything before we loaded everything in the vehicle, because he realized we were rushing things a bit, caught it and saved me.....
Movies is the only industry using firearms, that has set a standard....
You violate basic safety rules to get the shot, i.e. point weapons at a person or a camera (understandably)....
-but then-
Do not require every person handling weapons to be trained on them, understand them and the safety rules and make them responsible for the safety precautions that go along with the weapons...
Cops probably do have the highest rate of negligent discharge because they have 100 times the exposure of the average person to conditions that could create a negative discharge....
The military does very well consider the conditions they operate, probably less exposure than cops in garrison, but in training and combat, have multiple and different weapons fired from multiple positions in the fog of war, but they still have accidents as well....