The correct answer is sign yellow dog contracts
Yellow dog contract is a contract between an employee and an employer in which the employee agrees not to join a union. This is seen as an employment term; If the employee joins or organizes a union, he or she can be fired. In the United States, this practice is now illegal, but it was once quite common, used as a tool to force people to give up their right to organize in exchange for job security. Labor organizers vigorously protested the practice of drafting yellow dog contracts as working conditions, and as a result, the practice was banned in 1932 under the Norris-LaGuardia Act.
