Remember when buildings complexes had multiple entrances ? It is increasingly rare nowadays. Using private but publicly accessible ground as thoroughfare is on the way out too. Fences go up everywhere - though 9/11 is only one part of that security paranoia... My apartment building in La Defense is the only one left on our street with a single layer of access control - two is most common and three is the standard nowadays (and when I was a child, in the early 80's, there was none and it was normal). I don't want my city to feel like a compartmented facility.