The regulation of buyers' agents is a matter affecting the public interest for the purpose of applying chapter 19.86 RCW. Activities of buyers' agents prohibited under RCW 46.70.180 (11), (12), or (13) are not reasonable in relation to the development and preservation of business. A violation of RCW 46.70.180 (11), (12), or (13) constitutes an unfair or deceptive act or practice in trade or commerce for the purpose of applying chapter 19.86 RCW.