The super defcon 1 lockdown secret rooftop of the set of a movie as it was being filmed. I have exactly 0 excuse for being above the set even when there isn't a movie being made. There were security patrols and the whole block was taped off. Ingress was done in the twilight hour of a sunny day, and rooftop access attained through a mixture of social engineering and terminal friendship. Of course, I must protect my friends and fellow roof-dwellers, so I cannot say more.