U.S. authorities may soon operate the most stringent new U.S. pre-clearence  screening facility at Dublin Airport's in the soon to open Terminal 2.
If it goes ahead the new customs and immigration facility will subject passengers to such scrutiny they will be treated as domestic passengers when they land in the U.S.

The list of new pre-clearence procedures under consideration includes photographing baggage, allowing customs officers to see pictures of the luggage on screen while they check passengers' documents.

Irish authorities are quick to assert the primacy of Irish law in their own jurisdiction, however, insisting that passengers will remain in Irish territory and under Irish law until long after the flight takes off.

"It is not the US immigration area, it is the preclearance area so they remain in Ireland,"a spokesperson for the Department of Transport told the Irish press.

Ireland is the only other country that has a customs pre-clearence facility outside of the U.S. Once a passenger has cleared it they have no queues to join, no further processing, and no further questions. They have cleared customs and immigrant and may travel freely with the U.S.