Cal. Welf. & Inst. Code § 5976.5

(a) Notwithstanding any other law, and except as otherwise provided in this section, a hearing held under this part is presumptively closed to the public.
(b) The respondent may demand that the hearing be public and be held in a place suitable for attendance by the public.
(c) The respondent may request the presence of any family member or friend without waiving the right to keep the hearing closed to the rest of the public.
(d) A request by any other party to the proceeding to make the hearing public may be granted if the judicial officer conducting the hearing finds that the public interest in an open hearing clearly outweighs the respondent’s interest in privacy.
(e) All reports, evaluations, diagnoses, or other information filed with the court related to the respondent’s health shall be confidential. The respondent may at any time petition the court for an order sealing these records or any other court records in a proceeding held under this part. Notwithstanding any rule of court prohibiting records kept confidential by law from consideration for sealing, if such a petition is filed, there shall exist a presumption in favor of sealing.
(f) The fact that evidence is admitted at a proceeding held under this part shall not be the basis for admission of that evidence in any subsequent legal proceeding.
(g) Photographs, recordings, transcripts, other records of proceedings held under this part, and testimony regarding proceedings held under this part shall not be admissible in any subsequent legal proceeding except upon motion by one of the following in that subsequent legal proceeding:
1. (1) The respondent.
2. (2) The county behavioral health agency, the public guardian, or the public conservator.
(h) In a proceeding held under this part, this section shall not affect the applicability of paragraph (2) of subdivision (c) of Section 5977.1, make admissible any evidence that is not otherwise admissible, or permit a witness to base an opinion on any matter that is not a proper basis for that opinion. The admission or exclusion of evidence shall be pursuant to the rules of evidence established by the Evidence Code, including, but not limited to, Section 352 of the Evidence Code, and by judicial decision.
(i) Before commencing a hearing at the respondent’s first court appearance, the judicial officer shall inform the respondent of their rights under this section. At subsequent hearings, the court is not required to advise the respondent of their rights under this section upon finding that the respondent understands and waives the additional advisement of their rights.