Scabby the Rat, embodied in those huge, inflatable rodent balloons you see on Chicago sidewalks, long has been the bane of employers.Labor unions have deployed Scabby for years to publicize their disputes with employers.Often, Scabby targets not just the primary employer with whom the unions are warring, but secondary employers as well.Secondary employers typically are neutral businesses that have a business relationship with the targeted primary employer.Scabby then is trotted out to embarrass or shame the secondary into …