For the Greeks to placidly lie down and let the EU roller of virtue flatten them?
With only a majority of four Papandreou is toast. When this referendum is decided it's entirely possible that a new leader will get Greece out of the EZ. That is a very high probability.
No big deal there but other indebted countries in all probably may just decide to do the same.
Any that remained could easily have their debts debased by the existing puffed up EFSF.