Filling cars with cement? Maybe, but that could alienate the general public. Chaining themselves to various buildings? Definitely, but they first must figure out which "lock-down" technique to use. An aerial assault, possibly some parachutes? Get real. Billboard liberation? Oh, yes.

But these particular young rabble-rousers were also anarchists, nineties-style, congregating to parse strategies of "culture jamming," "billboard liberation," artistic media manipulation and alternative economics.

Billboard liberation amounts to property destruction and I personally can't advocate that kind of behavior. But I must confess I do get a chuckle when I see a bus shelter ad featuring a too-thin underwear model turned into a ghastly skeleton with no more than a few simple strokes of a black magic marker.