When I was in the Air Force there was a guy who ignored one of those. He powered up one of the radar systems with a guy inside. The guy made it out without getting fried but did get quite a dose.
The guy who powered it up almost didn’t survive though.
That is why the only key to the lock belongs in the workers pocket.
I will get in medium/high voltage gear without my own lock, but only after watching someone else put their lock on, and staying with that person.
Funny what happens in the Air Force. When I was Exec of a Security Police squadron, we had one cop give another a permanent part in his hair right down the middle of his head with a .38 while they were practicing their “quick draw”. The guy with the part was always pretty squirrley, but after that we had to discharge him.