I am sorry, but no, you cannot have the lock box combination! Working with buyers, I often get asked "Can I have the lock box so I can take measurements?," or "Can I have the lock box so I can show my parents my new house?" The Division of Real Estate is very clear on this subject. Providing a perspective buyer unauthorized access to a property by themselves creates numerous consumer harm issues; such as possible theft, property damage, injury, personal safety, and trespassing. As such, our Colorado Commission has reiterated that such action would be a violation of Section 12-61-113(1)(n) of the Colorado Revised Statutes, which states "having demonstrated unworthiness or incompetency to act as a real estate broker by conducting business in such a manner as to endanger the interest of the public." As a consequence, disciplinary action my be taken whether or not there is actual harm caused by allowing a buyer or other third party unaccompanied access without the listing broker's authorization.
This applies to appraisers, inspectors, etc. What does your State's Real Estate Commission say?