D.C. Mun. Regs. tit. 23, § 717
717.1 The holder of an on-premises retailer's license may permit a patron to bring to and consume on the licensed premises an alcoholic beverage that the licensee is permitted to sell or serve under its on-premises retailer's license; provided that the alcoholic beverage is opened by an employee of the establishment. However, the holder of an on-premises retailer's license shall not permit any alcoholic beverage opened on the licensed premises to be removed from the licensed premises.
717.2 The holder of an on-premises retailer's license shall be permitted to charge a corking fee not to exceed twenty five dollars ($25).
SOURCE: Final Rulemaking published at 51 DCR 4309 (April 30, 2004); as amended by Final Rulemaking published at 55 DCR 12991 (December 26, 2008).