California Code, Public Utilities Code - PUC § 2894

(a) Notwithstanding subdivision (e) of Section 2891, the disclosure of any information by an interexchange telephone corporation, a local exchange telephone corporation, or a provider of commercial mobile radio service, as defined in Section 216.8, in good faith compliance with the terms of a state or federal court warrant or order or administrative subpoena issued at the request of a law enforcement official or other federal, state, or local governmental agency for law enforcement purposes, is a complete defense against any civil action brought under this chapter or any other law, including, but not limited to, Chapter 1.5 (commencing with Section 630) of Part 1 of Title 15 of the Penal Code, for the wrongful disclosure of that information.

(b) As used in this section the following terms have the following meanings: