Md. Code, Business Regulation § 10–311.1

(a) A producer or refiner of motor fuel may not include in any agreement or contract entered into with a service station dealer any provision that directly or indirectly limits or waives any right of the dealer to:

(1) petition any governmental authority or body; or

(2) lawfully advocate or oppose any governmental or regulatory action with respect to any matter.

(b) Any provision in an agreement or contract that violates the provisions of subsection (a) of this section is deemed to be void and unenforceable.