In this Section, "loiter" means for a person to: Remain on a public street, sidewalk, or pathway, including one privately-owned but used by the public in general, so as to obstruct the free passage of a pedestrian or vehicle after a regular or special police officer has notified the person that the action is unlawful and has requested the person to move; Remain in or on a vehicle on a public street, sidewalk, or pathway, including one privately-owned but used by the public in general, so as to obstruct the free passage of a pedestrian or vehicle after a regular or special police officer has notified the person that the action is unlawful and has requested the person to move; Refuse or fail to leave a private business, commercial establishment, or parking lot that is posted with conspicuous "No Loitering" signs if the business or establishment is not open for business, and the person has been requested to leave by the owner, the owner's agent, or a regular or special police officer, unless the person: Has written permission from the owner, lessee, or operator to be present; or Is window-shopping under conditions and at a time of the day or night that would be considered conducive to that activity; Refuse or fail to leave a private business or commercial establishment that is open for business, or a parking lot of the business or establishment, after having been requested to do so by the owner or the owner's agent; Refuse or fail to leave a public building, public grounds, or a public recreational area, or a parking lot of a public building, public grounds, or a public recreational area, after being requested to do so by a regular or special police officer or by a regularly employed guard, watchman, or other authorized employee of the agency or institution responsible for the public building, public grounds, recreational area, or parking lot if the circumstances indicate that the person has no apparent lawful business or purpose to pursue at that place; Return, for no apparent lawful business or purpose, to the same public or private property from which the person was asked to leave and not return for 30 days. This Section does not prohibit picketing or orderly demonstration by labor unions or members of the public. A person who loiters is guilty of a misdemeanor and, on conviction, is subject to: For the first written offense, a written warning requesting an individual to move; and For a second written offense, a fine not exceeding $500.00 or imprisonment not exceeding 30 days, or both; and For a third written offense and subsequent written offenses, a fine not exceeding $1,000.00 or imprisonment not exceeding 30 days, or both. No person shall be charged with a violation of this Section unless and until the arresting officer has first warned the person of the violation and the person has failed or refused to stop the violation.