Misspelled words won't discredit a group's sincerity of cause. I think these people will have a difficult time being passive and trying to subvert the tea party movement, simply because it has no leader to it.
The best way to deal with these people is to document people being disruptive with video so they can be exposed for what they are. Just like with the spit-gate and N-gate, the proof of a hundred video cameras is our best defense.