All transient merchants, peddlers and solicitors, and all other persons similarly engaged who do not have a place of business within the city, shall at all times when so engaged, carry their license on their person. All other licensees shall post their licenses in their places of business near the licensed activity. All licensees shall display their licenses upon demand by any officer or citizen.
('69 Code, § 4.04) Penalty, see § 10.99