I don't buy this story. I call BS. There is a deeper agenda that someone is trying to sell. Granted there could be an idiot out there may shoot at an armored vehicle on training once. Afterall an idiot shot a hole in the Trans-Alaska Pipeline in 2001.
However, given the amount of LE attention such an incident would generate it probably wouldn't happen again.
I think the story is made up to so the fed pukes can justify a 41,000 acre land grab that would otherwise generate a lot of public opposition. It's easier to sell if you tell the public it's for the safety of their NG personnel.
Never trust the fed pukes when it comes to land issues (or most issue for that matter). Just ask any Indian. Throw in useful idiots like bunny-huggers and eco-nazis and it gets even murkier.