Athens News interviewed SYRIZA's economy expert (and potential finance minister) (`No unilateral action for Syriza,' says Yiannis Dragasakis: | Athens News). The reporter pressed him on what SYSRIZA will do in case of a confrontation. He diplomatically says that he doesn't expect a confrontation and thst the current situation is a lose-lose for the EU and Greece and SYRIZA wants a win-win soltion, but then adds:

...you are right to suggest that we should have suitable contingency plans for any eventuality in order not to be caught unawares. It's good to have such plans without publicising them too much.

So they do prepare for the eventuality, good.

For the case of a run on deposits, he says:

Our political position is that we don't seek unilateral action unless we are provoked. This means that if a situation arises for which we are not responsible, but one which jeopardises our national or social security, the government will not hesitate to take all necessary and feasible measures, even beyond the constraints of formal legitimacy. But this would imply that the other side is in breach of its statutory obligations. After all, financing the Greek banking system through the eurosystem is a paramount obligation of the ECB and national central banks which provide the liquidity necessary for eurozone economies to function properly. It's not some sort of charity that the ECB grants to eurozone states whenever it so pleases.

The "even beyond the constraints of formal legitimacy" sounds like a stark warning.

_{*Lunatic*, n.
One whose delusions are out of fashion.}