There is much confusion about what constitutes foreign earned income with respect to the residency location, the location where the work or service is performed, and supply of the salary or fee costs. Foreign residency or extended periods abroad among the tax payer is a qualification to avoid double taxation. Let's change one more fact in example: I give a $100 tip to the waitress, and also the waitress is definitely my woman. If I give her the $100 bill at home, it's clearly a nontaxable...