They hired workers to cross the picket line if a group of workers went on strike.
Step-by-step explanation:
The strategy that the companies use to stop strikes from growing is :
They hired workers to cross the picket line if a group of workers went on strike.
The members of the union cannot work during a strike, as the union can legally impose fines if the member violates its rules. So, they resign from the union and cross the picket line.
