To me this has a background stench of blackmail.
I just hope that someone has had the sense to put a contingency plan in place in case the need arises for a car and passenger service to be brought into operation at short notice.
We should keep in mind that strikes can be used in many ways, and by various players, not just the workers. In the past there have been cases of employers imposing conditions onto a workforce with the deliberate intent of fomenting strike action where that would be of benefit to the employer.
Maybe the short term pain of a slight disruption to car and passenger services would be a price well worth paying in order to get a cost effective and affordable sea link finally put in place, a thing that our government have been singularly remiss in not having done YEARS ago.