Monagesque in France
If you are a citizen of Monaco, you have freedom of movement in Metropolitan France, but not the rest of the Schengen Area or EU, where you can travel for 90 days in a 180 day period without a visa. There is basically no way to check that a Monagesque citizen has not violated their visa-free stay in the rest of the Schengen Area because there are of course no border checks between France and any of its Schengen Area member neighbors.
Sammarinese in Italy
Very similar situation to Monaco here. If you are a citizen of San Marino, you have freedom of movement in Italy, but not the rest of the Schengen Area or EU, where you can travel for 90 days in a 180 day period without a visa. There is basically no way to check that a Sammarinese citizen has not violated their visa-free stay in the rest of the Schengen Area because there are of course no border checks between Italy and any of its neighbors.
Vatican City citizen
Vatican City citizens do not have freedom of movement in any other country. So if you are a Vatican citizen you have visa-free access to the Schengen Area, but no freedom of movement. This leads to the kind of insane edge case where if you were a US/Vatican citizen with no EU/EEA nationality (like the Pope for instance) you have the right to freely be in Vatican City for as long as you want, but you can only travel to Italy for 90 days in every 180 day period. So be careful. Vatican City obviously does not have an airport.
Here’s for even more insanity, imagine that a Monagesque citizen worked for the Catholic Church and became a Vatican citizen. Kind of insane visa requirements for that hypothetical individual.
Andorran citizen
Andorra has a unique situation. Like the Vatican, Andorra does not have an airport because it is so mountainous, so to get in and out of Andorra you will need to enter the European Union/Schengen Area. But they are not a member of the European Union or Schengen Area, and do not have freedom of movement outside of their territory. So if you are an Andorran citizen and you were somehow barred from entry from the Schengen Area for whatever reason there would be no way for you to leave your country, making you trapped. Fortunately this rarely happens and Andorra has very good relations with its neighbors.
Now imagine for a second if you were an Andorran/Sammarinese dual citizen. Mwahaha. You have freedom of movement in Italy and San Marino, and in Andorra, but you are limited to 90 days in the rest of the Schengen area. Just… ugh.
Saint Pierre and Miquelon
Saint Pierre and Miquelon is a really weird place. It is a tiny French territory off the coast of Newfoundland and Labrador, Canada. It is technically possible to take a boat from Saint Pierre et Miquelon in international waters to the rest of France without going through Canadian waters. Most people don’t do this and transfer in Canada if they are going to Saint Pierre. But… if for whatever reason Canada wouldn’t allow a French citizen into Canada in order to fly to Saint Pierre and Miquelon it would be fine because if you transferred through Montreal you would be staying in the international wing of the terminal, so Canada would have basically no say.
Now, if Canada started to do preclearance in Saint Pierre et Miquelon when flying to Canada that would totally screw over any French citizen trying to get back to Metropolitan France without transferring through Canada. I think this is unlikely, but its an amusing legal edge case to think about.
Summary
The only other country in the world (using the UN definition) without an airport is Liechtenstein, but Liechtensteiners have freedom of movement in the Schengen Area/EEA/European Union through treaty. So there’s no way for a Liechtensteiner to be trapped in their country.
Freedom of movement is a great idea between democracies, and I find these edge cases where someone could inadvertently violate their visa very fascinating. In the case of a Monagesque or Sammarinese citizen who was to violate the terms of their time in the Schengen Area, how could the Sammarinese citizen be effectively punished? If you were to deport the Sammarinese citizen back to San Marino, they would still have freedom of movement in Italy. I suppose that the EU would issue a fine to the Monagesque citizen who was in Italy too long? That’s probably what they would do because simply deporting them is not going to prevent them from reentering Italy, given how Italy is only a 30 minute drive from Monaco.
Is this crazy? Probably.
Is this interesting? It is to me.
How do you think these insane situations would work in practice?