Pretty much standard procedure at most clubs; leave a loaded gun unattended while downrange and you are gone. Another big no-no is handling your gun at the firing line while someone is downrange.
I've had the second one happen several times. When I arrived back at the firing benches, I gave a stern lecture about range safety to the morons and said that would be their only warning. Most offenders realize why they were wrong, a couple challenged me with the 'who left you in charge?'
Wow your post brought back a lot of bad memories. I was a 40 year member of a large club around Albany NY and I would wear out a key board telling about the things I saw on our ranges.
For many years I was a officer or director sometimes over lapping as head of pistol, rifle or skeet committee chairman. I was also a long time NRA instructor and range officer.
Our club had a large membership it was centrally located in the middle of 3 large cities and many towns and it also had days/times it was open to the general public. Non members were charged a nominal fee and many times members helped people sight in or fix gun problems.
Not going to give specifics here but having bozos argue with you over common sense rang safety rules was common. The biggest one was who do you think you are, I have been shooting for X amount of years and I'm safe, know what I'm doing! Touching guns when the range was declared safe & people were down range was; well I'm only adjusting the scope, it's not loaded, I have it pointed off to the side the action is open, I know what I'm doing.
I try to be nice, but after telling the same person a few times I would bounce them from the range. I got to the point as R.O I would give one gentle reminder (depending on how egregious the violation) a much sterner one and for #3 YOUR OUT OF HERE! A real serious violation and you were gone fast the first time!
Some of these bozos were willing to fight over it and I was challenged a few times. It was a unpaid position and if serious enough trouble maker I would call the police and have them escort the idiot out.
Most times the responding officer was a shooter at the club and totally understood what was going on and handled the situation well!