Reading this thread got me thinking about what would happen if you unintentionally arrived early in a country (specifically port or airport - if it's by road just hang tight a mile or two from the border!) for which you required a visa?
For example, a flight that was due to arrive at 1am in the destination country caught a strong tailwind and arrived at 23:30 the day before. Does anyone have experience of this?
Similarly for unintentional overstays - I have had a flight delayed 12 hours (3pm scheduled, 3am +1 day actual departure) where we were bused from the airport to a hotel in Lisbon. If I required a visa to be in Portugal at the time and was leaving on the last day of its validity, how can that be handled? Doing exit passport control 4 hours before the flight?