Am I being incredibly obtuse or has my 11 years out of the UK spawned a whole bag of expressions with which I am not familiar.
"Unexpected gathering of streakers? (5,3) ?L?S? M?B
Flash Mob, class mob, glass mob????
The article doesn't mention it, but I think there was an earlier use in a Larry Niven short story, involving teleportation as a standard method of travel. Can't remember the title, though,