Zynga Inc. has won a dismissal with prejudice from a class action alleging it misled consumers with “special offers.” And the San Francisco gaming company behind Farmville has the U.S. Supreme Court’s decision in AT&T Mobility v. Concepcion to thank for getting off the hook.

When Rebecca Smith first filed the suit in 2009 on behalf of players of YoVille, Zynga and other co-defendants couldn’t force arbitration because California state law held that certain class waivers in consumer arbitration agreements were unconscionable.