It shall be a misdemeanor, punishable as prescribed in PCC 9.02.010, for any person in charge to knowingly create or maintain nuisance activity on property in his or her actual or constructive possession or control or to knowingly omit or refuse to perform any legal duty relating to the abatement or removal of a nuisance activity. Each calendar day that nuisance activity remains unlawfully upon property shall constitute a separate offense; provided, however, that criminal conduct of third parties shall not constitute a violation of this Section.