Mass. Gen. Laws ch. 43A, § 12: General meetings authorized; limitations of chapter

Section 12. This chapter shall not abridge the right of the inhabitants of the town to hold general meetings, as secured to them by the constitution of this commonwealth; nor shall this chapter confer upon any representative town meeting in any town the power finally to commit the town to any measure affecting its municipal existence or substantially changing its form of government without action thereon by the voters of the town at large, using the ballot and the check list therefor.