In last week’s column a reader wondered if he would be denied re-entry into the U.S. because he failed to submit the outbound portion of the I-94W card to airline staff at the time of departure from the U.S. (The I-94 card is given to all non-immigrant travelers to the U.S., and is meant to record their arrival to and departure from the country. The card must be surrendered by the traveler at the point of departure.)

We replied that there was no definitive answer to the question because there have been many instances where travelers to the U.S. have had no problem returning, even though the I-94 wasn’t surrendered at the previous departure from the country. Having said that, U.S. law does require that travelers submit the card when they leave, and provides a remedy for those who fail to do so.

For those who traveled to the U.S. and left the country in accordance with the terms of admittance, if they wish they can mail the I-94 to Customs and Border Patrol (CBP) at an address in Kentucky, though the agency’s website advises, “If you departed by a commercial air or sea carrier (airlines or cruise ships), your departure from the U.S. can be independently verified, and it is not necessary to take any further action, although holding on to your outbound (from the U.S.) boarding pass -- if you still have it --  can help expedite your re-entry next time you come back to the United States.”

What CBP means by independently verifying an air or sea departure is what we explained last week, that when a traveler checks in to leave the U.S. his/her travel information is electronically recorded and submitted to CBP. This system, though, is far from 100% verifiable, and CBP is having difficulty in implementing a definitive system for recording departures.

For those who left the U.S. by land (for example, driving to Canada) or – if they should be so lucky! – private plane, CBP advises that those with I-94s should submit them to the agency to ensure proper recording of the departure.

“If you do not validate your timely departure from the United States, or, if you cannot reasonably prove you departed within the time frame given to you when your entered, the next time you apply for admission to the U.S., CBP may conclude you remained in the U.S. beyond your authorized stay.  If this happens, your visa may be subject to cancellation or you may be returned immediately to your foreign point of origin,” CBP says.

Such travelers can send the I-94, with other proof of timely departure (for example, a boarding pass issued in Canada) to DHS-CBP SBU, 1084 South Laurel road, London, Kentucky 40744.

When checking the U.S. consular websites in both Dublin and London, the Dublin one says it is not necessary for those who left the U.S. by commercial airline to mail the I-94 to the above address if the traveler still has it. Yet the London one advises the opposite.

“Sometimes due to an oversight the card is not removed. If this occurs, the passenger's departure from the United States will not be registered with the CBP,” says the London site (http://www.usembassy.org.uk/dhs/cbp/i94.html).

So go figure. Clearly, as The New York Times recently reported, CBP is having a difficult time properly recording those who leave the U.S.