Back in the 60's a big wig was severely injured when walking past an honor guard.
He had a cold and turned his head to sneeze and a young soldier mistook his movement as being a motion to allow him to inspect his rifle.
The soldier brought his rifle into position to hand it off just as the man sneezed and somehow the bayonet ended up in the big wigs eye.
Been a long time, so I don't remember who the victim was, but I think he was with the defense department or the state department.
Some parade rifles are permanebtly disabled, with the bolt welded shut. Since the Garand is a favorite for firing salutes at funerals or special occasions they are less likely to be welded shut.
Removing the bolt and replacing it later is not difficult. removing the bolt gives a visual cue that the rifle is harmless. Also when the butt is grounded hard the bolt of an autoloader can fly back under inertia and snap shut, distracting the man doing the drill. So its probably best that the bolt either be imovable or removed during drills.