So you've returned home from a trip to the US to discover that the little I-94 card is still attached to your passport. If you departed by a commercial airline, your departure from the U.S. can be independently verified, and it shouldn't be necessary to take further action BUT, holding on to your outbound (from the U.S.) boarding pass can help facilitate your reentry next time you come back to the United States. If you departed by land, private vessel or private plane, you will need to take steps to correct the record . 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 you entered, the next time you apply for admission to the U.S., Customs and Border Protection (CBP) may conclude you remained in the U.S. beyond your authorized stay. If this happens, your waiver may be subject to cancellation or you may be returned immediately to Canada. So what can you do? If you f...