California Code, Business and Professions Code - BPC § 17591

It is unlawful for any person to do any of the following: using the “do not call” list for any purpose other than to comply with this article or applicable federal laws; denying or interfering in any way, directly or indirectly, with a subscriber's right to place a California telephone number on the “do not call” list; causing a subscriber to participate in and be included on the “do not call” list without the subscriber's knowledge or consent; selling or leasing the “do not call” list to a person other than a telephone solicitor; selling or leasing by a telephone solicitor of the “do not call” list; charging a fee to place a California telephone number on the “do not call” list; and a telephone solicitor, either directly or indirectly, persuading a subscriber with whom it has an established business relationship to place his or her telephone number on the “do not call” list, if the solicitation has the effect of preventing competitors from contacting that solicitor's customers.