To be clear, businesses and other private parking lot operators can tow your car at any time for any reason as long as it is in compliance with State statues and Town ordinances since you are parked on private property.
Before they can tow a vehicle, however, State law requires that all private lots that tow must have a sign prominently displayed that states that parking is restricted to certain uses, that violators may be towed, and a phone number for retrieving the vehicle. Additionally, the Town requires that the Police Department be notified of such a towing situation within 30 minutes, that no fee will be charged unless a vehicle has been attached to the tow truck prior to the arrival of the owner, and that the sign must state that credit and debit cards are accepted for payment.
For a full list of requirements, see Section 8-78 et seq. in the Town Code and Section 8-4 in the Town Charter.