No REALTORS® shall be required to participate. A requirement to participate in a multiple listing service in order to gain and maintain REALTOR® membership is an inequitable limitation on its membership (from Official Interpretation No. 1 of Bylaws, Article I, Section 2, adopted by the Board of Directors of the National Association, November 15, 1960). However, if a REALTOR® chooses to participate in the activity, the REALTOR® should be required to exchange information on the same basis, according to the same rules and costs imposed on all who participate. M