Let's keep on message folks - localities are barred from enacting carry restrictions. The South Milwaukee proposal to make carry in an establishment for "violating a sign" is such a restriction. A person refusing to leave a private establishment when told to leave by an agent of the owner can be prosecuted for tresspass already.
Wisconsin Statutes § 66.0409(2) provides that no political subdivision (defined as a city, village, town, or county) may enact an ordinance or adopt a resolution that:
"[R]egulates the sale, purchase, purchase delay, transfer, ownership, use, keeping, possession
, transportation, licensing, permitting, registration or taxation of any firearm or part of a firearm, including ammunition and reloader components, unless the ordinance or resolution is the same as or similar to, and no more stringent than, a state statute." Source: http://www.lcav.org/states/Wisconsin.asp