You don't threaten to leave, the whole point of unions is to attempt to equalize a negotiation when workers can't easily get another job. Dockworkers don't thre

You don't threaten to leave, the whole point of unions is to attempt to equalize a negotiation when workers can't easily get another job. Dockworkers don't threaten to go work at a competing port, they threaten to stop working and shut down the dock.