Article IV(D) of the Regional Lockbox Rules and Regulations states that keys may only be used “for the purposes of gaining authorized entry into real property.” A cooperating agent must receive authorization before entering a property.

The authorization is often contained in the showing instructions of the MLS listing. When an agent follows those instructions, he or she receives authorization to access the property. Therefore, if the listing states "call before showing,” then an agent must call the property prior to using the key to gain entry access.

However, please keep in mind that the mere presence of a lockbox is not an invitation to enter a property.