Mich. Comp. Laws § 168.723: Ballot boxes; examination, locking.

Sec. 723.

Before opening the polls, each ballot box to be used at the election shall be examined by the board of inspectors of election and the contents, if any, removed therefrom; it shall then be locked, and the key thereof delivered to 1 of the inspectors, to be designated by the board. The said box shall not be opened during the election.