As an additional means of enforcement, the Building Commissioner may accept an assurance of discontinuance of any act or practice deemed in violation of any provision of this Outdoor Advertising Sign Code, from any owner or person engaging in such act or practice. Such assurance shall be in writing and shall specify a time limit during which such discontinuance is to be accomplished. Failure to perform the assurance shall constitute prima facie proof of a violation of any provision of this Outdoor Advertising Sign Code, which makes the alleged act or practice unlawful for the purpose of securing an injunctive relief from a court of competent jurisdiction.