 It may be considered a form of unjust enrichment or unfair competition, as in California's Business & Professions Code § 17200, which prohibits any "unfair or fraudulent business act or practice and unfair, deceptive, untrue or misleading advertising".Shills, or "potted plants", are sometimes employed in auctions.Driving prices up with phony bids, they seek to provoke a bidding war among other participants.