In the next week, the European Union will likely remove the United States of America from its list. This is partly due to the increase in U.S. Covid-19 case numbers, but it's also politically motivated. The U.S. continues to ban Schengen European visitors who have been there within the last 14 days.The EU would recommend against American visitors. However, each country sets its own entry rules. This means that while nothing can be changed, rules could change leading to more inconsistency or bans for American visitors.We have a return of regime uncertainty, which I've been writing about for over a year as a key driver in difficulty booking travel.You may not be able to visit a destination when you purchase tickets. But, it might still be available when you travel.In the event of a misconnection, what about changing the rules to enter any connecting city?What are the rules for returning to your country? (And what tests and vaccines are counted, and how recent?It is possible that American visitor rules will change. For example, many countries are dependent on tourism during peak season and may implement changes.The U.S. could also impose entry restrictions to prevent Europeans from being punished for their stupidity. For example, American Airlines CEO Doug Parker describes a European consultant who visited their Skyview campus.[W]e had a consultant from Munich come in. To get to the United States she flew to Cancun, where she stayed for two weeks. After that, she was allowed to enter. She felt safer in Munich than in Cancun. That's exactly what we were doing.The United States bans travelers from Germany who have been vaccinated, but welcomes Indonesians who are not vaccinated (where Covid prevalence is low). A German citizen entering the U.S. after being vaccinated, and passing a negative test (as required), is less likely to be exposed to Covid-19 than an American in a bar.