I don't think a boycott by CDers is going to have an effect on the company. In fact, it will solve their "problem" of having CDers trying on clothes in their dressing rooms.
Far better would be for CDers to visit their stores in great numbers on busy shopping days and make a point of trying on clothes. Going in pairs or groups would make a statement. We don't have to buy, just try them on. OK buy something small just to stay legit.