"Sometimes lessons are best learned the hard way" - Someone who learned lessons the hard way (me included)
I recall a number of times that Sai yelled at folks. Did he take it too far? Maybe to some, but I also take safety very seriously, so not to me. Why folks, typically the "I've been shooting all my life" or "I'm a weapons expert" types want to argue against clearly posted rules, is beyond me and when I have zero problems them getting yelled at.
The old guy one is one maybe different. I've taken my dad a bunch of times and I generally handled the casing and uncasing. That said, there were times when his muzzle discipline did wander a bit when shooting pistols, but nothing unsafe. As long as said old guy wasn't one of the types noted above. No excuse for "I wasn't aware", but different than those that think they know and disregard safety.