California Code, Financial Code - FIN § 6725

(a) Notwithstanding any other provision of law, an association or federal association may continue to recognize the authority of an attorney-in-fact authorized in writing to manage or to make withdrawals either in whole or in part from the savings account of a holder, whether minor or adult, until it receives written notice or is on actual notice of the revocation of authority, whether the revocation is express or by operation of law.

(b) Except as provided in Division 4.5 (commencing with Section 4000) of the Probate Code, written notice of the death or adjudication of incompetency of the account holder that is delivered to the office where the account is maintained shall constitute written notice of revocation of the authority of the attorney-in-fact.

(c) No association or federal association shall be liable for damages, penalty, or tax by reason of any payment made pursuant to this section.