Wis. Stat. § 422.416: Referral transactions prohibited.

(1) With respect to a consumer transaction no merchant shall give or offer to give a rebate or discount or otherwise pay or offer to pay value to the customer as an inducement for a consumer transaction in consideration of the customer’s giving to the creditor the names of prospective customers, or otherwise aiding the creditor in entering into a transaction with another customer or, without being limited by any of the foregoing, performing any other act or the occurrence of any other event, if the earning of the rebate, discount or other value is contingent upon the occurrence of an event subsequent to the time the customer enters into the agreement.

(2) A violation of this section is subject to s. 425.305.