Me. Rev. Stat. tit. 15, § 1464

The order to the witness and to the person having custody of the witness must provide for the return of the witness at the conclusion of the witness's testimony, proper safeguards on the witness's custody and proper financial reimbursement or prepayment by the requesting jurisdiction for all expenses incurred in the production and return of the witness and may prescribe such other conditions as the judge thinks proper or necessary. The order may not become effective until the judge of the state requesting the witness enters an order directing compliance with the conditions prescribed.