History
During the 1988 Democratic National Convention, the city of Atlanta set up an official "free speech area"[5] so the convention would not be disrupted. A pro-choice demonstrator against an Operation Rescue group said Atlanta Mayor Andrew Young "put us in a free-speech cage."[6] "Protest zones" were used during the 1992 and 1996 United States presidential nominating conventions[7]

http://en.wikipedia.org/wiki/Free_speech_zone