Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 149, § 25

Every employee in public work shall lodge, board and trade where and with whom he elects;  and no person or his agents or employees under contract with the commonwealth, a county, city or town, or with a department, board, commission or officer acting therefor, for the doing of public work shall directly or indirectly require, as a condition of employment therein, that the employee shall lodge, board or trade at a particular place or with a particular person.  This section shall be made a part of the contract for such employment.