Where notice has not been given that a sale by auction is subject to a right to bid on behalf of the seller, it is unlawful for the seller to bid himself or to employ or induce any person to bid at such sale on his behalf, or for the auctioneer to employ or induce any person to bid at such sale on behalf of the seller, or knowingly to take any bid from the seller or any person employed by him. Any sale contravening this rule may be treated as fraudulent by the buyer. (Prior code § 20-5-23)