A person may possess alcoholic beverages on the premises of a license holder if: (1) the alcoholic beverages are owned by a member of a club licensed for the sale of beer and wine or beer, wine, and liquor and are consumed on the premises; (2) the alcoholic beverages: (i) have been brought on the premises of an on–sale restaurant for consumption and use in a private dining room at a private gathering; and (ii) have not been provided by the license holder of the restaurant; or (3) a dance or social event is: (i) held on the premises of an establishment of a holder of a Class C license; and (ii) 1. advertised as being bring your own (BYO); or 2. sponsored by a member of the club or by a guest that a club member sponsors.
Maryland Legal Code