I disagree with this whole thread.
Baldwin was required to use the gun, it is not like it was his choice.
And there is no reason why an actor should be expected to know what the real person in the role they are playing should know.
It was not Baldwin's responsibility to learn about gun safety on his own.
It is the job of the armorer to teach the actors who need to know, what they should know.
And the main mistake was not Baldwin's.
While anyone familiar with guns would have opened and checked the gun, that was not Baldwin's fault for not knowing that.
The mistake was for there to be live rounds anywhere on the set, and in particular for them to be loaded in the gun.
So then the fault is really with the crew who brought the ammo, loaded it for "plinking", and then did not unload it.
Baldwin was required to aim at the camera for a fast draw scene.
He had no choice but to point at the camera, which just then also happened to be at the camera lady.