I've had similar problems, but not necessarily always at unsupervised ranges, but yes I can certainly relate to one's concerns regarding unsafe handling practices.
My BIL nearly blew my head off multiple times in a single day while deer hunting. Several of those close calls occurred due to him shooting over my head at deer that had been bumped up in front of us. At the end of that day we had stopped at an old abandoned stone cabin. We stopped there on the last leg of our long hike to take a break before walking the remainder of the way back to the vehicle. He was leaning against the opposite wall unloading his 8mm Mauser, the muzzle was point directly at me. If not for me being observant and, I simultaneously ducked out of the way of his muzzle at the very instant it discharged. My head would have been a blood stain on the wall if not for that. It was so close that I had small pieces of rock fragments embedded in the side of my head and face. At that point and considering the hunt was over, I grabbed my gear and walked home, which was about 4 or 5 miles. I was 16 yrs. old at the time and never hunted or shot firearms with him ever again.
But I've had quite a few very close calls. I was shooting at our local range a few years back, unsupervised range, myself and several other shooters had called a cease fire so we could walk down range to check and change targets. There was only one person at the line, we made it perfectly the clear that we were calling a cease fire. All of us had just started the 200 yards trek back when all of a sudden the guy up at the line started shooting his AR15. We all buried out faces in the dirt at the same time. Not yet realizing who was shooting I instinctively drew my sidearm, then the guy next to said, wait, wait, it's the guy at the line shooting. Talk about mad, we all yelled "hold your fire" "cease fire" multiple time, but he couldn't hear us because he had his ear plugs in. We ran the rest of the way up there, he was still shooting when we approached him. His idiotic reply was, come on, I'm not an idiot, I saw you guys, I wasn't shooting directly at you, what's the big deal, all while sweeping us with his muzzle. Are you kidding me, are there really morons like this at the ranges?
On another occasion while shooting at that same range a couple of trucks pulled up and started unloading their weapons and gear along with an ice chest full of beer. While it's not illegal to consume alcohol and shoot guns in our state, it is illegal to do so if you're posing a safety issue, such as sweeping people or handling them in some other fashion that poses a direct threat to others. It didn't take long for all of us to realize that these guys were already two sheets to the wind when they arrived. After looking down their muzzles twice, myself and another man approached them and said something. We were respectful but being this is a serious safety issue we were very direct. This was when they became belligerent, which was when I packed up and immediately left, enough is enough.
So yes, I'm a strong proponent regarding the necessity of range officers. But even with them I have experienced numerous problems at ranges, a lot of people just don't get it. So now days I often just drive out into the public lands and shoot where I know I'm the only one. I may not have the conveniences the ranges offer, but I also don't have to deal with a bunch of careless morons either.
SMOA