Well, I don't know about the USAF, but should I get a call about one of my Marines even if it is about an off base item, I take it seriously. Never was I called about a range thing. Usually it was drinking and/or driving issues or financial. Many times it ended with a guy one rank lower or losing his clearance.
At the same time, this kind of call would have gotten me to brief my platoon on range safety, advise them I got a call about "someone," and not much else.
The dumbest things I have seen at a public range?
1. A guy was shooting some surplus arms at a local 100yd range. Mostly an SKS and AK. I broke out my rifles and set up my bench while waiting on him to be done. Once he was done he came over and was asking about my choice and it was mostly polite, but something seemed "off" about him. Maybe it was the lack of knowledge, the SHTF talk or the surplus cammies he had on, but he seemed very ignorant yet paramilitary. I wrote it off as just me and him being a new shooter or something.
We went downrange and I was setting up my target when all of a sudden he pulled his handgun and started shooting from about 25yds back! As soon as he was done emptying his mag and was attempting (rather pathetically) to do speed reload, I tore into him verbally. By that time, I had sprinted back up to behind him yelling for him to stop and had been ignored. He left shortly after, and I never saw him again, but hope he learned better.
2. 1000yd range laid out much like I imagine the OP's is. I was at the 500yd line and was the only one at the range. I was done with a string and was about to check my targets when I heard a report from my right rear. Sure enough some guy had set up targets at the 800yd line and was shooting from the 1000yds line. I was sure since I was proned out for mine he must have missed me (despite my car being right behind him and my range gear being on the same bench his turned out to be on. So I started waving my hands and got a wave back then another shot rang out!
This guy was a piece of work. He assured me he was a sniper from the local base (there were none stationed there) and I was perfectly safe where I was. It was way too long of a walk to set targets on the target line so he was going to shoot where he was and I should just continue on. I just told him to hold off while I gathered my stuff up and left. I let him know that one more shot while I was downrange would result in me yanking his ID and returning it to his unit (turned out he was a mechanic). I gathered my stuff and left. Him I saw a few more times at that range area (Yuma, AZ), but never had another problem with him.
There my two worst idiots.