Private parks for the public?

New York has some high profile public spaces that are really private.  NYC's Paley Park, shown above, is a classic example of a privately-owned public space.  WNYC points out that the OWS crowd is occupying another such park, Zucotti Park.  As such they had on both a reporter and a Harvard Professor, you can pick the one you trust more.  Previously, former Rutgers Instructor Kristine Miller wrote a book on the subject.
h/t puk