Originally Posted by LiveWell
I always thought it was quite straightforward to determine whether or not you are a resident of a particular country.* For example, in the US they use the Substantial Presence Test ( 183 days during the 3-year period that includes the current calendar year and the 2 preceding calendar years... )
Surprisingly, prior to 911 the US authorities did not have any single tracking system to prove residency, particularly with regards to outbound dates - out of the US.
It was up to the resident to keep good and accurate records. Now though, airline passenger data is archived, and the INS(UCSIS) & IRS probably have direct or indirect access.
However the IRS generally still relies on the tax payer to come up with proof through good record keeping. Its the same in Europe. Its also widely known, that millionaire Executives with private jets, are able to sieve though many of the nets supposed to track movements.