No person under 18 years of age shall be allowed to entertain, with or without compensation, in licensed premises while liquor is being served or consumed, except that in Class A restaurants, clubs, and hotel dining rooms persons 17 years of age who are members of a musical group may entertain. Any person under 17 years of age will be permitted to entertain provided his/her parent is present
18- 553 C.M.R. ch. 102, § 3