Cal. PROB § 8481

(a) A bond is not required in either of the following cases: (1) The will waives the requirement of a bond. (2) All beneficiaries waive in writing the requirement of a bond and the written waivers are attached to the petition for appointment of a personal representative. This paragraph does not apply if the will requires a bond. (b) Notwithstanding the waiver of a bond by a will or by all the beneficiaries, on petition of any interested person or on its own motion, the court may for good cause require that a bond be given, either before or after issuance of letters.