I understand that this may vary depending on the disputed area. What happens, practically, when a person attempts to travel to a disputed area? Do they ever have to pass through two customs/immigration checks (one by each country), or have other multi-country problems, such as being sued or prosecuted in the courts of both countries over an incident that happened in a disputed zone? Do people born in disputed areas generally end up with dual citizenship because both countries treat them as born in their territory?
E.g. it is my understanding that the Falkland Islands are de facto under British control, but Argentina claims them. If an Argentinian travels to the Falkland Islands (and is allowed in by the British), does Argentina consider them to be in or out of Argentina in the sense of jurisdiction and residence? Would they be able to claim that they need not go through Argentinian customs and immigration on returning to the mainland because, per Argentinian law, they technically never left the country? Could a person living in the Falkland Islands claim to actually be a resident of Argentina and have that recognized by any country?
This question is not limited to the Falkland Islands.
I thought I read something about Uruguay going along with Argentina and cutting off travel to the Falklands. IIRC you fy there from Britain via the island of St. Helena by air.
Many other such locations, due to hostilities and fear of spying, foreigners are not allowed anyway.
If you google, there’s a number of countries (Syria, Iran, Iraq, UAE?) that will arrest you and dump you at the nearest border, then permanently ban you, if there is any hint you have been to Israel. Apparently at the Allenby/Hussein bridge crossing, Jordan and Israel will stamp a paper insert instead of your passport to avoid putting proof of your visit permanently in your passport. The Jordanians stick to the polite fiction you are visiting the Palestinian territories, not Israel. One item I read said - be sure to remove even the sticky residue from the stickers that they put on the outside of your passport during processing. Another travel site mentioned some backpacker who avoided these problems, but presented a Youth Hostel card that had been stamped by the Jerusalem hostel. No bribe was able to prevent the Damascus hostel from calling the police. Obviously they take this seriously.
I suppose the issue in any situation is whether one side wants to consider that you had no choice or act as if you actively supported the other side. Pre-existing residents likely are exempt. Local business people who do well may be seen as collaborators with the enemy; visitors often will be considered unwelcome, unless it’s expedient to ignore the situation, like Taiwan vs. China. Etc.
OTOH, I also read about some travel books being confiscated at the China border if the maps inside, for example show Taiwan or Tibet as a different country than China. But, the business activity with Taiwan has picked up, with a lot of travel back and forth and the central goverment in Beijing ignoring the question as often as it can, as long as nobody forces the issue. Every so often a politician may threaten to win the Taiwan government elections with a promise to decalre independence, but common sense about poking the tiger has prevailed… so far.