We had a weird thing happen a few trips ago, and I thought it might be worth mentioning.

We arrived at Dulles and it turned out that our connecting flight to St. Thomas (I think from Miami) had been canceled, so they put us on another flight on another airline out of Miami. Excellent!

What they didn't tell us is that this somehow broke the link to our return flight reservation, and so the computer cancelled our return flight reservation.

Fast forward 2 weeks.

We're sitting in the Best Western Emerald Beach in St. Thomas and decide to check-in via the iPad. Computer can't find our reservation. We have no reservation. Aieeeeeeee! Nooooo! Luckily we had booked it all through Travelocity, and they took ownership of the problem and spent 5 hours fighting it out with the airline for us! They got us on a plane the next day, but it was touch and go for a while.

Lesson learned - if you outbound flight gets changed, make sure you're return flight is intact!