Several years ago I was at some meeting in one of the Google buildings. During some lunch time (on a weekend) I was walking through the streets in Google campus looking around and at other (closed) buildings, just curious. And some Google security guard stopped me I must return back to that my meeting building. May the guard do that? Are the streets there really a Google private propery? There was no gate to enter the Google campus and I was looking like a normal geek.