Most of the seamen involved in the strike work in ferries or at the port (that's why there was a "national emergency": transport from and to the islands were disrupted). So the only foreign countries they will land on are either Italy or Turkey. Ocean going crews usually do not have these issues, their main issue is with collective bargaining (at a time when the shipping tycoons have amassed billions) and tend to be officers nowadays rather than sailors (although that's probably changing). The government subsidizes the shipowners to cover the smaller islands of the Aegean (which they don't do enough of, especially in the winter) so they could easily hold back the subsidies to pay for wage arrears. They could also pressure them on the issue of collective bargaining (but that's something the troika would surely frown on)

The road of excess leads to the palace of wisdom - William Blake