—cash mobber n.
—cash mobbing pp.
Unlike the phenomenon of a flash mob, in which hundreds of people show up in one public place at the same time to sing, dance, or otherwise create a stir, organized cash mobs vote on which local businesses to support and visit on a designated day so as not to overwhelm the staff.
—Michele Morgan Bolton, "A new flavor in buying locally: cash mobs," The Boston Globe, June 7, 2012
The phenomenon stems from the flash-mob trend, where people meet at a predetermined location to perform some synchronized action. With cash mobs, the action is spending money at a local business.
—Danielle Verbrigghe, "Local First Arizona planning 'cash mob' for Glendale, Mesa," Phoenix Business Journal, June 20, 2012
But the wine merchant did enjoy a steady flow of customers all day, thanks to a new social media called the "Buffalo Cash Mob."...
Nominations for what businesses will be selected for "cash mob" treatment are solicited online, and then the votes are tallied.
—Harold McNeil, "Buffalo Cash Mob helps local wine shop," The Buffalo News, August 6, 2011
The phenomenon is called 'cash mobbing' — a kind of flash mobbing in which people gather not to make some artistic statement but out of pure greed.
The cash mob — thought to be the first of its kind in Britain — was promoted through MySpace, the social networking site that has become huge business.
—"Forget flash mob, now there's cash mob," Daily Mail, September 28, 2006
Many thanks (but, alas, no cash) to Laurie Mullikin for spying this phrase.