Mich. Comp. Laws § 168.746: Ballot of challenged voter; endorsement concealed, identification prohibited.

Sec. 746.

To prevent the identification of said ballot, except as hereinafter provided for in case of a contested election, the inspectors of election shall cause to be securely attached to said ballot, with mucilage or other adhesive substance, a slip or piece of blank paper of the same color and appearance, as nearly as may be, as the paper of the ballot, in such manner as to cover and wholly conceal said endorsement but not to injure or deface the same; and if any inspector or other officer of an election shall afterward expose said endorsement or remove the said slip of paper covering the same, or attempt to identify the ballot of any voter, or suffer the same to be done by any other person, he shall, on conviction thereof, be deemed guilty of a misdemeanor.