Members and subscribers of rating or advisory organizations may use the rates, rating systems, underwriting rules or policy or bond form of such organizations, either consistently or intermittently, but, except as provided in sections 38a-667, 38a-670 and 38a-672, shall not agree with each other or rating organizations or others to adhere thereto. The fact that two or more admitted insurers, whether or not members or subscribers of a rating or advisory organization, use, either consistently or intermittently, the rates or rating systems made or adopted by a rating organization, or policy or bond forms prepared by a rating or advisory organization, shall not be sufficient in itself to support a finding that an agreement to so adhere exists and may be used only for the purpose of supplementing or explaining any competent evidence of the existence of any such agreement.