Not sure what is 'emphatically not true' with the OP. Americans are required to state global income over some threshold (I believe it was around $91K this tax

Not sure what is 'emphatically not true' with the OP. Americans are required to state global income over some threshold (I believe it was around $91K this tax year). Few other countries apply a tax to wages earned overseas by citizens. After passing a minimum threshold, tax treaties are applied to determine precise tax liability for the year.