You can have your free country, but not here

The policing of the protests during the 2004 Republican National Convention represents another interesting model of repression. The NYPD tracked every planned action and set up traps. As marches began, police would emerge from their hiding places — building vestibules, parking garages, or vans — and corral the dissenters with orange netting that read 'POLICE LINE – DO NOT CROSS,' establishing areas they ironically called 'ad-hoc free speech zones.' One by one, protesters were arrested and detained—some for nearly two days.
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Prominent examples of recent free speech zones are those set up by the Secret Service, who scout locations where the U.S. president is scheduled to speak, or pass through. Officials will target those who carry anti-Bush signs and escort them to the free speech zones prior to and during the event. Reporters are often barred by local officials from displaying these protesters on camera or speaking to them within the zone.

Free speech zone - Wikipedia, the free encyclopedia