Wash. Rev. Code § 67.70.220
If the person entitled to a prize is under the age of eighteen years, and such prize is less than five thousand dollars, the director may direct payment of the prize by delivery to an adult member of the minor's family or a guardian of the minor of a check or draft payable to the order of such minor. If the person entitled to a prize is under the age of eighteen years, and such prize is five thousand dollars or more, the director may direct payment to such minor by depositing the amount of the prize in any bank to the credit of an adult member of the minor's family or a guardian of the minor as custodian for such minor. The person so named as custodian shall have the same duties and powers as a person designated as a custodian in a manner prescribed by the Washington uniform transfers to minors act, chapter 11.114 RCW, and for the purposes of this section the terms "adult member of a minor's family," "guardian of a minor," and "bank" shall have the same meaning as in chapter 11.114 RCW. The commission and the director shall be discharged of all further liability upon payment of a prize to a minor pursuant to this section.
RCW 67.70.220
Effective date-1991 c 193: See RCW 11.114.903.