Cal. PROB § 4302

When requested to engage in transactions with an attorney-in-fact, a third person, before incurring any duty to comply with the power of attorney, may require the attorney-in-fact to provide identification, specimens of the signatures of the principal and the attorney-in-fact, and any other information reasonably necessary or appropriate to identify the principal and the attorney-in-fact and to facilitate the actions of the third person in transacting business with the attorney-in-fact. A third person may require an attorney-in-fact to provide the current and permanent residence addresses of the principal before agreeing to engage in a transaction with the attorney-in-fact.