(a) Trustees of independent school districts may not authorize any exclusive franchises on the right to negotiate on behalf of the district.(b) Consolidations under the Texas Education Code, Chapter 49, Subchapter B; detachments and annexations under Subchapter C; and tax base consolidations under Subchapter F are permanent in duration and districts may not enter into agreements that purport to limit the duration of the agreement. Nor may the parties create by agreement any right to cancel the agreement.