The Colorado Constitution assures the confidentiality of the registry... note the bold section of the amendment below:

(3) The state health agency shall create and maintain a confidential registry of patients who have applied for and are entitled to receive a registry identification card according to the criteria set forth in this subsection, effective June 1, 2001.

(a) No person shall be permitted to gain access to any information about patients in the state health agency's confidential registry, or any information otherwise maintained by the state health agency about physicians and primary care-givers, except for authorized employees of the state health agency in the course of their official duties and authorized employees of state or local law enforcement agencies which have stopped or arrested a person who claims to be engaged in the medical use of marijuana and in possession of a registry identification card or its functional equivalent, pursuant to paragraph (e) of this subsection (3). Authorized employees of state or local law enforcement agencies shall be granted access to the information contained within the state health agency's confidential registry only for the purpose of verifying that an individual who has presented a registry identification card to a state or local law enforcement official is lawfully in possession of such card.