Michigan Compiled Laws, Chapter 462. Railroads § 462.16

Sec. 16. If any common carrier or any agent or officer thereof shall, directly or indirectly, by any special rate, rebate, drawback, or by any means of false billing, false classification, false weighing, or by any other device whatsoever, charge, demand, collect or receive from any person, firm or corporation, a greater or less compensation for any service rendered or to be rendered by it for the transportation of persons or property or for any service in connection therewith than that prescribed in the public tariffs then in force, or established as provided herein, or than it charges, demands, collects or receives from any other person, firm or corporation for a like and contemporaneous service in the transportation of a like kind of traffic under substantially similar circumstances and conditions, or shall knowingly and willfully assist or willfully suffer and permit such greater or less compensation to be charged, demanded, collected or received, such common carrier shall be deemed guilty of unjust discrimination, which is hereby prohibited and declared to be unlawful. It shall be unlawful for any common carrier to demand, charge, collect or receive from any person, firm or corporation a less compensation for the transportation of property or for any service rendered or to be rendered by said common carrier in consideration of said person, firm or corporation furnishing any part of the facilities incident thereto: Provided, Nothing shall be construed as prohibiting any common carrier from procuring any facilities or service incident to transportation and paying a reasonable compensation therefor.