It is unlawful to march in any parade upon any street carrying any flag or banner, except the flag, colors or ensigns of the United States of America, or any of its military or naval organizations, including the National Guard, or the recognized flag or emblems of any friendly foreign nation or country unless such flag or banner bears some distinct name in letters clearly legible at a distance of at least 100 feet, or legend, design or insignia, clearly designating or descriptive of, or identifying it as the emblem of the persons, society, association or organization marching in such parade; provided, however, that this requirement shall not apply to any flag, banner, pennant or other device used for purely decorative or spectacular effect in any parade having no direct or indirect political purpose or object. In no case shall any American flag be carried which shall bear any lettering, advertisement or other defacement. (1961 code § 11.24.060.)