Anyone, whether it’s these people or somebody else, appearing at a TEA party with an agent provocateur sign, should be rudely accosted and hustled off of the scene.
Yes, take your cameras and be vigilant.
I’d recommend some Tea Partiers keep them busy while others get the police, who are always very close by to these events. Any roughing up and hustling off - any physical contact - would only give them the advantage, PR-wise, which is exactly what they want.
For an alternate tactic -- using their own "Alinsky Judo" against them -- see post #155 on this thread...
Ridicule can be used against these provocateurs very effectively.
(Even without the graphic, the sign/tactic should be effective -- especially if it is called to the attention of the media...)