“Clockwork Orange.”
Larry Niven, “The Last Days of the Permanent Floating Riot Club”, 1973. A band of thieves that used flash mobs as cover for their thefts. In Niven’s stories about Flash Mobs they were caused by a new technology, basically teleportation machines. He described many ways they changed his future society.
And now we have instant ways to connect mobs of people for purposes both good and bad, cell phones. The idea and effect is very similar. naturally you need a cadre of people who are brought up to include this behaviour in your social repertoire.
Ha, thanks for the flashback. I remember that now, though I had forgotten it. Was into Larry Niven in the 70s. I should go back an get a copy of Lucifer's Hammer. See if I still think it is as good as I remember it to be.