A 3-0 NLRB ruling found that the University of Pittsburgh Medical Center and it’s affiliate hospitals interfered with a union drive by prohibiting workers from discussing unionization with SEIU representatives. According to the decision, the medical center overstepped their right to ban union solicitation in areas where patients are being treated, by preventing union representatives from speaking with off-duty employees in any part of the hospital. The board didn’t weigh in on a related dispute over whether the medical center and it’s affiliated hospitals is considered a single employer under federal labor law.
See "Pittsburgh Hospital Interfered With Union Drive, Labor Board Says", Chris Opfer, Bloomberg, August 7, 2018