Those who have walked around the Loop undoubtedly have encountered Scabby the Rat.Scabby, of course, is the giant inflatable rat that labor unions often display to publicize their disputes with employers.Scabby and his inflatable sidekick, Fat Cat, last month met their match when the 7th U.S Circuit Court of Appeals ruled that a Wisconsin town lawfully could employ its signage ban to deflate the longtime representations of …