Every holder of a license to engage in, exercise, or pursue a business, profession, trade, occupation, or privilege shall conspicuously display the license at all times in some part of his place of business or activity where a person who has entered the place may readily see it; or, if he has no particular place of business or activity, shall carry the license and shall display it to any person who requests to see it. Provided, that in lieu of the above manner of display such license, when licenses are required for coin operated amusement devices, vending machines, and similar devices and equipment, the license may be placed on or attached to such devices or equipment in such position and manner that it will be clearly visible, and shall be so placed or attached that the license is readable. It is unlawful to fail or refuse to display the license as required in this section. (2011 Code § 5-3)