Truman Capote famously said "actors are dumb". While there have been intelligent actors who knew how to handle guns (people like Gary Cooper or Charlton Heston come to mind), I suspect most actors really are pretty dumb (based on their political comments, that seems to be true). I don't think safety with guns should ever come down to whether a flaky movie star checks his or her gun. Can you imagine some dipshit like Alyssa Milano knowing how to check a gun?
I think Arec Barrwin's culpability will come down to his being the producer and having apparently hired incompetent prop people and thereby running an unsafe film shoot.
Ignorance (dumbness) is absolutely no excuse. Baldwin is 63 years old; he’s been in the ‘business’ about 40 years and in those 40 years he has participated in films that had guns. No way was he completely ‘ignorant’ on gun safety. No way. He ignored safety protocols because he is arrogant and lacks the ability to think things through or consider anyone else besides himself.