It's much more likely they'll mismanage it, in which case Greece will self-destruct as hungry crowds riot in the streets, and the EU will plod along a bit longer while experiencing the "death of a thousand cuts".
“If Greece exits the EU and manages it well (highly unlikely) it will be the end of the EU as other member nations suffer “Greek envy”. “
That is why they have to make an example out of Greece. Radical leftists want to take over in larger European countries, and renounce their debts as well. The Podemos Party is rising in Spain.
Europe has prepared for a Greek default for years, it would be much harder to absorb larger countries defaults, everytime leftists win an election. It would be a huge incentive to elect leftists, just to get out of debt.
It is coming down to the wire, and Monday could well be it for Greek Default in terms of decision, even if it won’t be final until the 30th. If things don’t go well on Monday, emergency measures like closing banks and such could start hitting by Tuesday.