Md. Code, Business Regulation § 10–502

(a) Except as provided in subsection (b) of this section, a refiner or other supplier of motor fuel to a retail service station may not engage in, sponsor, promote, advertise, or otherwise perform or participate in a game of chance to be marketed or offered to the public at a retail service station in the State.

(b) (1) A supplier of motor fuel authorized under this title to supply retail service stations may, at such stations, sponsor, promote, advertise, or otherwise perform or participate in a game of chance if the retail service station dealer agrees to participate in the game of chance.

(2) A supplier of motor fuel authorized under this section to conduct a game of chance may not require a retail service station dealer to participate in the game of chance.