Bull.
I once pulled the hammer back—almost all the way; without locking—accidently and that sucker went off.
Scared the crap out of me and my knees started to wobble thinking what would have happened if my brother-in-law was downrange of me (he had just stepped back to the firing line).
It was a screw up on my part. I had no intention to make the piece fire, but you know about intentions. Lots of people get killed.
All the more reason that live ammo should not have been anywhere on that job site.