Wash. Rev. Code § 60.04.035
The legislature finds that acts of coercion or attempted coercion, including threats to withhold future contracts, made by a contractor or developer to discourage a contractor, subcontractor, or material or equipment supplier from giving an owner the notice of right to claim a lien required by RCW 60.04.031, or from filing a claim of lien under this chapter are matters vitally affecting the public interest for the purpose of applying the consumer protection act, chapter 19.86 RCW. These acts of coercion are not reasonable in relation to the development and preservation of business. These acts of coercion shall constitute an unfair or deceptive act or practice in trade or commerce for the purpose of applying the consumer protection act, chapter 19.86 RCW.
RCW 60.04.035