Md. Code, Bus. Reg. § 16-215

(a) Unless authorized by a license, a person may not accept delivery of unstamped cigarettes. (b) On receipt of a package of cigarettes, a retailer, subwholesaler, or vending machine operator immediately shall: (1) examine the package to find out whether tobacco tax stamps are affixed properly to the package as required by § 12-304 of the Tax - General Article; and (2) reject any unstamped or improperly stamped cigarettes by: (i) returning them to the seller or consignor; or (ii) delivering them to a common carrier for return to the seller or consignor. (c) (1) There is a presumption that any unstamped cigarettes in the possession of a retailer, subwholesaler, vending machine operator, or wholesaler are held in violation of this subtitle. (2) A retailer, subwholesaler, vending machine operator, or wholesaler who holds unstamped cigarettes has the burden to prove that the cigarettes are not held in violation of this subtitle.