Every peddler and solicitor or itinerant merchant shall carry the permit issued to him or her under this chapter on his or her person at all times while engaged in selling, peddling or soliciting in the city. It shall also be the duty of every peddler and solicitor to exhibit such permit when requested so to do by any law enforcement officer or other department personnel designated by the Chief of Police, or any person with whom the peddler, solicitor or itinerant merchant attempts to do business.