[1] Example. You don't want to become a resident of Australia because they tax foreign residents on foreign earned income and dividends. Thus you enjoy yourself there on tourist visas. Yet suddenly war breaks out and the law of physical presence test is not rescinded even though you can not travel out of Australia because of the war. Sane law can become insane. Example #2. You assume that your European citizenship will not tax you if you are not resident of your citizenship country. Suddenly the EU starts taxing directly and they do not honor such an exemption and I bet they will implement a wealth tax in one form of another eventually.
I believe the economic citizenship programs of the EU nations (even Spain will given you residency if you buy a 300,000 euro property) are a tax trap. They will change the rules on Europeans. It is SOBO (statement of the blatantly obvious) they will not allow Europeans to escape their tax obligations by residing outside the EU, because as they raise taxes on the productive citizens of the EU, the productive Europeans will of course seek out tax havens. Thus the EU will have no choice but to close the loophole that exists. The EU will harmonize with the USA system of taxation (that is what FATCA is for) where you are liable for taxes no matter when you reside. Mark my word! The EU has no fiscal choice because the EU is bankrupt! You never want to be a citizen of a bankrupt nation (or economic union) which has unassailable taxation powers. The Troika is untouchable. They have proved in Greece, they can do what ever they damn well please to you Europeeons (as in peons).
Meanwhile the powers-that-be really do intend to lock you inside the border.