It's not theoretical. It spans lots of areas, from trivial food safety (you're forbidden/required to wash eggs depending on the country), to social (can't allow

It's not theoretical. It spans lots of areas, from trivial food safety (you're forbidden/required to wash eggs depending on the country), to social (can't allow / can't deny education for women), and many others. Countries have explicitly conflicting laws in many cases and effectively force people to break another country's laws.