They're going to be on the Common, rather than by the Harbor? Don't they have any sense of propriety? (Well, obviously not.) I like the idea of joining you for tea, but need to avoid any gatherings where there is likely to be heavy police presence. So, probably not. Can you bring low-tech but civilized-looking apparatus for boiling water? Or would it be better to make tea at home and bring it in a thermos?

I would like to warn you of a potential problem. I'm not at all confident there won't be actual tea-partiers wearing frilly hats and drinking tea on the Common. It's HARD to make fun of a group as far off the deep end as the tea partiers. It may not be possible to exaggerate their silliness to show disapproval or disagreement, when their silliness is so all-encompassing.