Just because one doesn't know all the facts doesn't mean outside forces have to be evoked to explain a chain of mistakes that lead to a tragedy. It's OK for a person to say, I don't know. And I don't know what happened on the set of Rust.
The thing that I actively do not like about the theories of sabotage being floated around (including the implication from Gutierrez-Reed's camp that maybe one of the crew who walked off due to safety issues was the one of brought and loaded the live round), is that it conveniently deflects blame. And, frankly, it doesn't make anyone actually look better.
Suppose you are an investor in this film--tell me again how destroying the production helps you? It means that the film will never make a profit. And the negligence on set might even mean that there won't be insurance payouts. If you're an investor, don't you want to get the film finished so you have at least a chance at a return on your investment?
Suppose you are a crew member who is upset about lax safety. Are you really going to intentionally put a loaded gun on that set, knowing it could be fatal to one of your co-workers (including a child character who was in the film)?
And even if there was some element of
intentional harm (ie someone got to the prop table and put a live round in the prop gun), that gun still went through "checks" by both Gutierrez-Reed and Halls before it got into the scene that was being rehearsed.
Again: it boggles my mind that any crew member was comfortable putting live rounds into a weapon they knew would be used in a scene in a film. (Was Gutierrez-Reed among those doing this target practice?). The most likely series of events, for me, is that someone was playing with the gun and failed to unload it when done. Gutierrez-Reed, when loading the gun with blanks, either did not notice the round or (if she was unaware it had been used for target practice between takes) assumed it was also a blank. Then the gun went to Halls, whose check was also cursory enough that he didn't notice the live round.
The real question is: who brought live rounds to this set? Because even if you want to believe that alien lizards working for the mob or a psychopath disgruntled camera operator loaded that gun, faking such an "accident" simply doesn't work unless there are actual bullets around.