A vote on formation of a union does not mean employees are forced to join it. A union also doesn't mean anything if there isn't an agreement with the employer.

A vote on formation of a union does not mean employees are forced to join it. A union also doesn't mean anything if there isn't an agreement with the employer. A union also doesn't mean anything if it's members are not going to withhold their services if they don't come to an agreement that is deemed acceptable by it's members. Unions are also about leveraging power. While someone can try to start a union with any number of people, how much they can actually negotiate is going to hinge a lot on that number. Is 55% of the workforce enough to have significant leverage? I don't know and it depends on what the union wants. Would the union be able to reach an agreement with the employer that would force the others to join the union? That would seem like quite a stretch to me.