I know of an incident that happened on DOE leased property. Security badge needed to get into the building, but not the parking lot.
Road rage incident, guy on his way to the facility, followed by another guy into the parking lot, where second guy produced a gun. DOE security pounced on him, took him away. Besides the assault, he was charged with gun in prohibited area. Never did find out if he was convicted, matters not.
We were all informed, you can have your gun in your car, park on the street next to the lot or park across the street, its all good. Park in the lot with a gun, big problem.