Mass. Gen. Laws ch. 127 § 86H
The commissioner of correction may permit an inmate to leave a state correctional facility to address a public gathering, provided that the commissioner receives a request in writing from the sponsor of the public gathering desiring such an address, the inmate selected to present the address is recommended by the committee established under the provisions of section forty-nine A, the inmate leaves the correctional facility in the custody of an officer or employee of the department and remains in such custody until returned to the facility by said officer or employee, and the sponsor of the public gathering bears the cost of transportation for the inmate and the officer.
An inmate shall, at all times during his absence from a correctional facility under this section, be considered as in the custody of the officer having charge of the correctional facility, and the time away from the facility shall be considered as part of the term of the sentence.
Mass. Gen. Laws ch. 127, § 86H