It depends on how they do it. If they simply renegotiate or go through various arbitration/adjudication processes, then the impact can be small. (Of course if they don't accept the outcome of these processes, then it'll be worse.)

That said, on this level it's almost 100% politics. There are many ways to get out of these unfair deals made in times of desperation, the question is - like you said - are they worth it or not.