A federal appeals court has ruled that AT&T may prohibit its unionized field technicians from wearing white T-shirts with black stripes displaying the phrase "Prisoner of AT$T."

The workers, based in Connecticut, were in a labor dispute in 2009 and wore the shirts to protest increasing healthcare costs. About 200 workers were suspended for refusing to remove the shirts. The National Labor Relations Board (NLRB) had sided with the technicians from the Communications Workers of America in 2011, but a federal appeals court set aside that decision Friday.

According to the Friday ruling by the US Court of Appeals for the District of Columbia Circuit: