There’s no justice like random mob justice

With apologies to the writers of the Simpsons, quite possibly one of the most captivating ideas I’ve seen on the web in a while crossed my radar today: Flashmobs, as Cory called them on boingboing, although I think Instamobs would be better as it wouldn’t channel visions of “funny” craplets. Edit: My mistake, Sean called them FlashMobs, Cory called them FlashCrowds. I still like Instamob better, for some reason I can’t really put my finger on.
The concept is simple while remaining entirely bizarre. Meet up with other people you don’t know. Receive instructions about where to meet and what to congregate around. Appear at the designated time. Act like you know everyone else in the mob. Leave at the designated time. Go home.
Apparently the last time this happened, someone got concerned in advance and called the cops; some boingboing readers fought along with this, claiming the idea of having an unfocused mob could lead to a “mob hijack” and thus somehow turn the mob evil. Jack F. Mancilla writes:

Have we not seen a few cattlemen turn a stampeding heard of animals following their nose from one direction to another.
A “MOB” could easily be turned from the direction of gentle friendliness into a stampeding group of mindless people searching for their own survival by a single/few people consciously driving them in a chosen direction.
The organizers of the MOB may have no such intent, but the actions of the MOB can be hijacked.
Who are the organizers, and who could use such a MOB?

But this just strikes me completely off kilter, largely because of what limited experience I have with mobs and, more importantly, decentralization.
A properly designed mob would be, in effect, the perfect decentralized system. There would be no one leader, only programmed behavior within the mob. Much like birds flying in a V-formation, people may follow one another, but there is no one defined leader. Thus, people trying to change the operational rules would almost assuredly be ignored out of hand by those members of the mob who have no reason to divert from the plan.
As it is, I wish I could’ve gone to this; not because it’s performance art, not because it’s some stand against silly corporate rules, but because how many times in your life do you get a chance to join a ten minute mob?