Do we have a cite for this law?
It’s a federal law. And yes the supreme court repealed it, but then congress basically said “oh, yes we can”, slightly rewrote it and passed it again.
Lot’s of states also have their own law about this CA does, not sure if WI does.
It is a forfeiture for a person to knowingly possess a firearm (concealed or otherwise) at a place that the person knows or has reasonable cause to believe is within 1,000 feet of the grounds of a school. Wis. Stat. § 948.605(2)(a).