It is an unfair labor practice for an employer:

(1) To interfere with, restrain, or coerce symphony musicians in the exercise of their rights guaranteed by this chapter;

(2) To control, dominate, or interfere with a bargaining representative;

(3) To discriminate against a symphony musician who has filed an unfair labor practice charge or who has given testimony under this chapter;

(4) To refuse to engage in collective bargaining.