Mass. Gen. Laws ch. 140 § 183D
No innholder, common victualler or person owning, managing or controlling a cafe, restaurant, or other eating or drinking establishment shall require any person to pay a minimum charge or cover charge unless a sign is conspicuously posted at every entrance to any dining room or rooms where such charge is required, in letters no less than one inch in height, stating that a minimum charge or cover charge shall be charged and also stating the amount of charge; provided, however, that no such innholder, common victualler or person owning, managing or controlling a cafe, restaurant or other eating or drinking establishment shall require a person under thirteen years of age to pay a minimum charge or cover charge. Whoever violates this section shall be punished by a fine of not more than fifty dollars.
Mass. Gen. Laws ch. 140, § 183D