That just ensures that nobody will go and travel to Greece. It is their biggest revenue source and it sounds like they are prepared to screw that up.
They've fleeced their own (semi) productive class now they are moving on to other countries.
If Greece can break lose from the EU and stop the flow of migrants, it will be just about the only country on the Med that is safe for travel. Besides that, lots of people will want to support Greece if they break away from the bankers and other elitists.