I think they keep people out and keep people in. I can see a scene out of the Fifth Element, "the is a police lockdown" - controlled entry/exit, easy to do.
but I wonder what would happen in a fire? I'd feel trapped
19 posted on 06/22/2012 9:47:09 AM PDT by NativeSon
( Grease the floor with Crisco when I dance the Disco)