I love the idea of flash mobbing for productive ends.. If there's anyone with interest in this kind of activity, as the season rolls around, let me know! I would be happy to help organize events!
From the article: “The more tedious the work we have, the better,” Jones said, smiling. “Because part of Crop Mob is about community and camaraderie, you find there’s nothing like picking rocks out of fields to bring people together.”