Yes in the Marine Corps you can go to the brig for an accidental discharge, and you will go if you do.Really? Even on the range? In the Army I don't know how many times I've heard the RSO go: Ready on the right-ready on the left-BANG!
It's less scary to fire a weapon at a target walk forward knowing that behind you to your left or right another Marine is going to take a shot as soon as you get down in the prone position, when EVERYBODY follow the four basic rules. It was constant to watch yourself and the guy next to you. Anyone could check anyone for not follwing safety rules.
Things have gotten relaxed in the Marine Corps, you used to go to the brig just for having rust on your rifle. Safety will never be compromised.