Back to the remarks about Cayman Islands non-tax. According to World Factbook, Cayman Islands, is an overseas territory of the U.K. NO DIRECT TAXATION IS PAID TO THE U.K. because the islanders saved a sinking ship during a terrible storm in 1788 and King George III promised to never impose a tax on the Cayman Islands.
The U.S.A., unlike many European countries, taxes its citizens on their worldwide income regardless of where they make it. U.S. citizens, including Obama, Debbie Wasswerman Shultz and Romney, pay U.S.A. taxes on overseas income.
By the way, Cayman Islands is considering an income tax on their citizens.