Md. Code, Alcoholic Beverages and Cannabis § 17–2501

(a) A public club, room, or other unlicensed establishment, at a location under the control or possession of the establishment, may not:

(1) sell or serve alcoholic beverages to a member or guest;

(2) keep alcoholic beverages for a member or guest;

(3) allow a customer to consume or to be served or given alcoholic beverages from the supplies that the customer has previously purchased or reserved; or

(4) sell, serve, keep, or allow to be consumed setups or other component parts of mixed alcoholic drinks to a member or guest.

(b) A person that operates a business establishment for profit that is not licensed under this article may not knowingly allow a customer to bring alcoholic beverages for consumption into the establishment.

(c) A person that violates this section is guilty of a misdemeanor and on conviction is subject to a fine not exceeding $1,000.