Mont. Code Ann. § 16-2-107
16-2-107 No open alcoholic beverage container or alcoholic beverage consumption on premises of agency store
16-2-107 . No open alcoholic beverage container or alcoholic beverage consumption on premises of agency store. An agent and the agent's employees in an agency store may not allow any alcoholic beverage container to be opened on the premises of an agency liquor store or allow any alcoholic beverage to be consumed on the premises of an agency liquor store, nor may any person open an alcoholic beverage container or consume any alcoholic beverage in an agency liquor store.