Mich. Comp. Laws § 453.361
That the board of managers, or executive committee of any agricultural, horticultural, industrial fair, exposition society or horse fair of this state, or any corporation organized under the laws of this state to hold any exposition or industrial fair, is hereby authorized to appoint as many citizens of this state policemen as shall be necessary for their exhibition, whose duty it shall be to preserve order within and around the grounds of said society or fair; to protect their property within said grounds; to eject all persons who shall be improperly within the grounds of said society, or who shall be guilty of disorderly conduct, or who shall refuse to pay the fee, or observe the rules prescribed by the society or fair. Said policemen shall have the same power during the time said exhibition shall continue that a constable may have by law in serving criminal process and making arrests, and in addition, may arrest any person for the commission of any offense mentioned in section 2 of this act.
MCL 453.361