A few years ago my wife my daughter and I went to D.C. for a sightseeing trip. This was a couple years after 9-11.
Our vehicle was less than reliable but we went anyhow and I as a concerned father/husband took my KelTec P3AT along in my right front pocket in case we broke down en-route.
I don't remember what I was looking for but we wound up on the Pentagon campus where it is clearly posted "No firearms" etc.
My wife knows I carry but didn't put 2 and 2 together when she suggested I go ask the security guards how to get out of there. They were the last 2 people I wanted to have a face to face with.
I played the usual man thing that "I don't need to ask directions" until she got fed up and went herself.
We left without incident but the very next day we were on the same road looking for the same exit. My wife insisted the take the same turn we took the day before because "We must have missed the turn" that we were looking for and damned if I didn't wind up in the exact same pace I as the day before.
I don't know what the penalty is for carrying on Pentagon property pu I imagine it isn't a slap on the wrist and a "Naughty naughty"