Wash. Rev. Code § 50.04.275
The term "employment" shall not include services performed by a person who is participating in a performance sponsored by an employer whose North American industry classification system code is within "711110," "711120," "711130," or "712110," so long as the person receives no remuneration other than a nominal stipend and the employer does not have more than three individuals in its employ during any portion of a day during the calendar year.
For purposes of this section, "stipend" means a fixed sum of money paid periodically to defray expenses. The stipend is presumed to defray the person's incidental expenses involved in participating in the performance, including, but not limited to, meals, transportation, lodging, costumes, supplies, and child care.
RCW 50.04.275