Md. Code, Alcoholic Beverages and Cannabis § 11–2704

(a) In this section, “premises” includes a building, parking lot, picnic grounds, terrace, or grounds that form an integral part of the licensed premises.

(b) Except as provided in subsection (c) of this section:

(1) an individual may not consume, display, or possess on the licensed premises an alcoholic beverage not purchased from the license holder; and

(2) a license holder may not allow an individual to consume, display, or possess on the licensed premises an alcoholic beverage that is not purchased from the license holder.

(c) A holder of a beach and amusement park license may grant written permission to a patron of the license holder’s beach or park to bring and consume on the licensed premises an alcoholic beverage not purchased from the license holder.