Md. Code, Commercial Law § 13–304

A seller may not use any general referral sales technique, plan, arrangement, or agreement by which a buyer is induced to purchase merchandise, real property, or intangibles on the representation or promise of the seller that if the buyer furnishes to the seller the names of other prospective buyers of like or identical merchandise, real property, or intangibles, he will receive a reduction in purchase price by means of a cash rebate, commission, or credit toward balance due or any other consideration.