The SO had one idea and I had another. They could be used separately or together.
1) We don't want to do the "free speech zone" thing, right? That is not change, other than to change ourselves into Bushites. Ick But..."town hall" meetings have that word "town" in the name. They are intended to let residents, as in constituents, of an elected official engage in face to face communication. And these Baggy people are by all accounts being hauled around from town to town in by their whoremasters. So...what if it was required to show proof of residency at the door to get in? Not anything restrictive mind you--a driver's license, state ID, utility or other bill, anything that proves you live in the district of the person speaking. It's possible that some of the Birther/Baggers are indeed local, so they would get in. That's fine. The idea is to keep out the carpetbaggers, the paid whores for the corporations. Cut their numbers, thin the herd. They find this a grave threat to their bullying ability. It will also give them something to rant about outside, so folks in the venue can engage in genuine dialogue.
2) Sing out, Louise! As soon as the first nutcase leaps to his feet and starts chanting, you stand up and start singing like Harry Carey was on the mike upstairs. "God Bless America" would be a good start--let the oh-so-patriotic persons keep their rant on during that. My personal choice would be "We Shall Overcome." Hell, "Take Me Out To The Ballgame" will do. Ridicule is part of the effort.
Prepare, perhaps, by bringing along a few printouts with lyrics and, if at all possible, a friend or two with a good loud singing voice and a nice set of at least pewter gonads. (Pewter contains brass but also weaker elements. This describes many of us, metaphorically speaking, when it comes to displays of courage along with good humor in the face of incipient stormtroopers.)
Other ideas? We need to come up with a solution to this, and pronto. Yes they are being portrayed in the media fairly unsympathetically, but they're being shown as (1) sincere, as their sponsorship by insurance-industry front groups is mentioned all too briefly and (2) effective. Damn these reps who are giving up, shutting up and fleeing the scene. They should resolve, as you already have (right?) to stay as long as it takes.