The security people should work teamed up with someone with a video camera to record any conversations. The camera person could also have a walkie talkie or cell phone if you have more than one security team.
The odds are if you look prepared in this manner the totalitarian-wannabes will leave you alone. Keep in mind that they are essentially cowards. If they do and it cannot be defused, the camera provides evidence for later.
-Eric
Here is a post by freeperfromnj from another thread. Thought you might find it interesting.
Did you see Curtis Sliwa there? He called in to Monica Crowley's WABC radio show from the site. He said he should have worn his rain gear because the anti-American pigs were spitting on him. He said they were carrying the Israeli flag with swastikas painted on them. He said there were some freepers there counterdemonstrating.