Fundamentals of Human Resource Management 5th Edition by Raymond Noe, John Hollenbeck, Barry Gerhart, Patrick Wright

Exercise 20

The Case of the Misguided Supervisors
Recently, when a union sought to organize the nurses at a California hospital, the nursing supervisors, called charge nurses, didn't understand their proper role in the process. While the union was distributing cards for the nurses to indicate their desire for a representation election, several of the charge nurses participated in the union's meetings and decided they wanted to join. Some of these charge nurses also encouraged nurses who reported to them to support the union as well.
One month before the election, the hospital discovered that charge nurses had supported the union even though their positions in the organization qualified them as supervisors. The charge nurses stopped advocating for the union, and some even encouraged nonsupervisory nurses to vote against representation. The election went ahead, and the union won representation.
The hospital challenged the election because of the pro-union activity by the nurses. However, the NLRB and the court both upheld the union.
Why would an organization care whether its supervisors speak in favor of or against union representation?