Wis. Stat. § 779.90: Notice of existence of lien.

A person is deemed to have notice of a prepaid maintenance lien if:

(1) That person has actual knowledge or reason to know that the lien exists on the seller’s property;

(2) That person has reason to know that the seller regularly demands or accepts prepayments for maintenance;

(3) The seller engages in a type of business that generally requests or demands prepayment for maintenance; or

(4) The lien was filed as permitted in s. 779.89.