There are strict rules about this. Only the armorer and the actor are to handle the gun. If a third person gets involved, then the gun can't be considered safe. Like if you walk away from your luggage at the airport, it's compromised. And there are meant to be third eyes on the situation at all times, as well, to ensure neither person does something weird. There are people hired to do this job and those people are not actors whose job is distinct.
I have no reason to think that Alec Baldwin can tell blanks from live ammunition. But secondly, once he's opened the gun, they can no longer attest to the gun being "cold." So he can't test the gun on his own. In that regard, it DOES matter.
This could JUST as easily been Jensen Ackles. Baldwin's role as EP is the thing to examine, but you just simply can't let actors be the ones in charge of whether or not there's live ammunition in the gun. They aren't subject matter experts and there's someone else whose job it is to ensure that. The actors job is to do what they're meant to do with the gun and nothing else. They aren't supposed to go rogue with it in any fashion. It opens the door to more danger. What the actor should do above all else is follow the protocol.
