Seems like someone would figure out that a dummy round loaded in a pistol could have a pretty big hole drilled in the case. Nobody will see the side.
Could or could not.
“Depending on the manufacturing process, some have a hole in the casing. High-end dummies don’t, according to Carpenter.”
The way you check dummy rounds is simple. Point the gun at the ground, away from any people, and in a safe direction. Dry-fire every chamber and add a couple of clicks for good measure.
That is the best practice. If possible, that is done so the actor can observe
Had that been done the live round would have been discovered before someone was shat.