There is no need for a plan B. The Greek government is still on track for its plan A:
Agree to any negotiation but never finalize anything. Start making silly claims (ww2 payments) yourself. In the mean time all of their personal assets are long safe. When finally nobody sends money to Greece anymore they'll go bankrupt.
Then tey'll blame it on everybody but thelselves.
Why they don't take on the chucrch ?
Why they don't take on the superwealthy Greek ?
Answer is easy, politicians from any party are very closely tied to both of those parties = corruption.
This looks obvious to me too, and I find this whole discussion silly.
I think you're dead wrong here.
The consequences of defaulting are literally haunting. If you think the world debt load looks bad and is a runaway freight train, the end game results of defaulting are literally worse.
They will have no currency that will be accepted by the surrounding european countries = no trade, no export, no import
They will have no natural resources = no commodity trades, they will already have to sell whatever commodities they have at a bigger loss (think iran selling oil to china while oil plummets in value)
They will be completely cut off from the international banking system = no ability to internationally transact
I mean, those things start the exact second they declare a default.
Who knows what punishments ensue, because they wont be allowed back into the international banking system.
Defaulting might bring structural changes that are desperately needed, but it could (likely) also send them bank into the medieval times for 10-15 years. A complete generation of people will have suffered because of it. And by suffering, I mean people literally dying in the streets from starvation.
The trick is that while their government wont hold EUROs, the citizens will. And it will create this fascinating micro economy where the Greek government begins issuing a new currency, which no one will prefer, while everyone backroom deals in Euro.
If you thought it was difficult to raise revenue through proper tax enforcment now, think about what happens post default. It will be even worse.
(for the record, the most practical decision is clearly to default. you preserve your sovereignty, but you lose a lot of lives in the process)