When I was working for a military contractor our cubes were in a large open space that anybody who had building access could wander around in. We had Leper Lights in case of visitors so we’d know to keep an eye out and watch what we were talking about.
One unusual case was when we were building some gear for the German Air Force. They didn’t get the Leper Lights but for a couple months we had black and yellow striped tape marking the limits where the reps could go. We called it the Maginot Line but I don’t think they liked that.
We had smaller labs where the actual hardware was and they had Cypher Locks on the doors. I had at one point six different combinations a month to memorize. Only two things kept me sane. Half changed on the 1st and half on the 15th, and after a couple times my fingers knew the combo without engaging my brain. “Hey, DD? What’s the new combo for [lab]?”
“Um…” Walk over to the nearest Cypher Lock and touch the switches without clicking them. “One seven three five.”
One project we were the sub-contractor for Lockheed and when we brought over the engineering model for their software development, we were the reason for the Leper Lights. It felt strange.