It is unlawful for any person to operate any pool or billiard hall in the city where games of cards are permitted to be played, or beer, as defined in this code, is kept, sold or consumed, without first making a regulation and enforcing the same and keeping posted in a conspicuous place, terms of such regulation which shall read as follows: No person under 21 years of age permitted in these premises. (Ord. 98-1, repealed and replaced, 2000; Prior code §12-6(a))