> Either way, scanning that space is probably a waste of bandwidth

That's what the DoD wants you to think ;)

Maybe a bit off topic, but years ago I had a home linux server, used for usenet/torrenting. I was just poking about on it one day and ran some variation of netstat and could see a connection with a 6.x.x.x range IP address, which stood out. I didn't know a whole lot about networking at the time (still don't), couldn't say if I had misinterpreted what I saw in the netstat output. But it stood out so I looked it up and hoo-boy, it was a shock to see who owned that IP range, Army Information Systems Centre. I chalked it up to them maybe running a torrent tracker or something, or was the DoD in my PC?

Service providers (especially mobile ones) often squat on large, unused IP blocks (of which the DoD has plenty of), especially at peak capacity. I suspect this is what occurred here.