One of my units was doing a live mission at Camp Ripley MN several years ago. It was an active SCIF.
We had out our wire, seismic intrusion detection equipment deployed, MPs with M-60's patrolling around outside the wire.
A National Guard 2nd Lt leading a patrol though the woods discovered
our site and believing us part of their NG war game said she was taking us prisoner.
She wasn't convinced that she should just move along and find a softer target until she was shown that the weapons pointed at her had live ammo.
Kind of hard to miss an M-60 ammo belt containing the real thing and M-16s with no pretty little red blank adapters.