Hmmm, I'm afraid a must respectfully disagree on the premise that the truthers don't act the same wherever they go.
For instance, you get one at a clinton/obama or Rudy McRomney rally, everybody knows they aren't welcome.
Rally security will harass them, rally go-ers will scorn, insult or berate them in any one of a number of ways and everyone feels they generally don't 'fit in'. Most of the time they are ejected and are relegated to a place across the street. Likewise, the truthers tend to go to those events not primarily to help the candidate but to get as much attention as possible from people who may - in a parallel universe - listen, and to try to be as loud as possible.
This isn't what they do at Ron Paul rallies though. We rarely if ever say anything to them; so they blend in, hang around the campaign booths and areas where active ralliers congregate, they really look like they are part of it (the campaign) - but damnit they just won't stop with that crap. It doesn't hurt rudy mcromney because at those rallies they are little more than outsider amusement, but I would contest they are detrimental to Dr. Paul because you just can't stop some people from thinking of them as 'internal' to Ron Paul's campaign.
Anyway, just my two cents.. i just think they're damn annoying.