A copy of every permit issued to an applicant shall be prominently displayed within the area of proposed activity. If the permit-issuing authority deems it advisable, the applicant may be required to cause a sign to be erected bearing the permit number, date of issuance, name of applicant, and such other information as the permit-issuing authority may reasonably require. The permit-issuing authority may specify the type of and, within reasonable dimensions, the size of the sign.