This whole "crashing the Tea Party" business is a little goofy. The one party I actually went to - in State College on April 15th of last year - had a guy in a tea bag costume whom I was pretty sure was making fun of the gathering. Nobody paid him any mind, because he was a fifty-year-old hippie wearing a man-sized tea bag. "Griefing" is at the same time older than folks give it credit for, and less serious.
Don't get excited until the guys in the black ski masks show up. And it shouldn't matter if the guy holding a blatantly racist sign is a griefer or for real - you still should ask him to go home & leave his racial hang-ups in the closet with the white hood, regardless of whether his klan drag is meant ironically or in dead earnest.
(I should mention that I haven't run into or even seen pictures of these legendary, mythical anti-Obama racist protesters in the actual flesh. It can be hard to tell the mobys from the actual David Dukes online.)