Wis. Stat. § 19.96

Any member of a governmental body who knowingly attends a meeting of such body held in violation of this subchapter, or who, in his or her official capacity, otherwise violates this subchapter by some act or omission shall forfeit without reimbursement not less than $25 nor more than $300 for each such violation. No member of a governmental body is liable under this subchapter on account of his or her attendance at a meeting held in violation of this subchapter if he or she makes or votes in favor of a motion to prevent the violation from occurring, or if, before the violation occurs, his or her votes on all relevant motions were inconsistent with all those circumstances which cause the violation.