Wis. Stat. § 879.09: Notice requirement satisfied by waiver of notice.

Persons who are not minors or individuals adjudicated incompetent, on behalf of themselves, and appointed guardians ad litem and guardians of the estate on behalf of themselves and those whom they represent, may in writing waive the service of notice upon them and consent to the hearing of any matter without notice. An attorney, or attorney-in-fact, for a person in the military service may waive notice on behalf of himself or herself but cannot waive notice on behalf of the person in the military service. Waiver of notice by any person is equivalent to timely service of notice.