California Code, Health and Safety Code - HSC § 7111

A cemetery authority or crematory may make an interment or cremation of any remains upon the receipt of a written authorization of a person representing himself or herself to be a person having the right to control the disposition of the remains pursuant to Section 7100.

A cemetery authority or crematory is not liable for cremating, making an interment, or for other disposition of remains permitted by law, pursuant to that authorization, unless it has actual notice that the representation is untrue.