Wisconsin Statutes Transportation (Ch. 189 to 195) § 195.11. Discriminations prohibited

(1) If any water carrier, or any agent or officer thereof, shall directly or indirectly, or by any device whatsoever, charge, demand, collect or receive a greater, less or different compensation for the transportation of persons or property or of any service in connection therewith than that prescribed in the tariffs then in force, or than it charges, demands, collects or receives from any other person, firm or corporation for a like and contemporaneous service, such water carrier shall be deemed guilty of unjust discrimination, which is hereby prohibited.

(2) It shall be unlawful for any water carrier to demand, charge, collect or receive from any shipper a less compensation for the transportation of property or for any service rendered or to be rendered by said water carrier, in consideration of said shipper furnishing any part of the facilities incident thereto; but any water carrier may rent any facilities incident to transportation and pay a reasonable rental therefor, but no payment shall be made by any carrier to an industry for performing any part of the service incident to the origination or determination of shipments which the carriers have assumed to perform under the provisions of the bill of lading.