Wis. Stat. § 814.51

The court shall have discretionary authority in any civil or criminal action or proceeding triable by jury to assess the entire cost of one day’s juror fees for a jury, including all mileage costs, against either the plaintiff or defendant or to divide the cost and assess the cost against both plaintiff and defendant, or additional parties plaintiff or defendant, if a jury demand has been made in any case and if a jury demand is later withdrawn within 2 business days prior to the time set by the court for the commencement of the trial. The party assessed shall be required to make payment to the clerk of circuit court within a prescribed period and the payment thereof shall be enforced by contempt proceedings.