We teach all cops to carry locked, loaded and safety off. If they are not comfortable with that, there are some "drills) we suggest.In a gun safety class in Cincinnati I attended long ago played us a dash cam video from a police officer doing a traffic stop on the highway. A fire fight ends up taking place between the Cop and the driver. The Cop tries to fire but nothing happens. You can hear him yelling shoot shoot shoot. But nothing is happening. The problem...... His weapon is on safe, and his brain is stressed in this adrenaline maxed situation. The police officer ended up getting killed sadly. My point to all of this is, you can train and train and train but when the moment comes your mind is racing and we don't always perform to how we train. If the Cop would have been carrying a Glock or firearm without a safety, he'd likely still be alive. I carry a Sig P365 quite a bit and it has a safety, and they make ones without it, it drives me nuts mine has a safety. So I train with it of coarse, but I much prefer carrying a Glock. I wish the Glock 43 could hold 10+1. Or I wish the G26 could fit in my pocket.
Wear your duty holster around your house with your gun charged, but not loaded. Then count the number of times the gun just "goes off". After 2 decades, the number is zero.
(Assuming they aren't carrying a Sig 320
This also works great for civilians that are worried about carrying loaded with the thumb safety off, or carrying a gun without a thumb safety.
We also suggest unholstering and holstering many times with the unloaded but charged handgun.
The vast majority of negligent discharges happen while reholstering.