[AuntB]

During the time this ‘camp’ was operating, we camped only a few miles from it and didn’t even know it was there. I’m glad I didn’t stumble on to it accidentally.

[Old Teufel Hunden]

"During the time this ‘camp’ was operating, we camped only a few miles from it and didn’t even know it was there."

From how the article was written, it sounds to me like the camp never actually got going. They had picked out a site but no training actually went on. If you had been camping a few miles away while training was going on, I would think there's a good chance that you would have heard gunfire.