air travel – How do you get the wrong boarding pass in these high security computerised days?

Something happened to me about 3 years ago, and I have been wondering ever since about how such a thing can happen in these days when security is taken so seriously, and data is handled mostly by computer, minimising the potential for human error. Names have been changed.

My boss, Alice Smith, and I, Bob Wayne, were flying back from the main Madrid airport to London Heathrow on BA. We checked in together (with hold luggage), handing over our passports and a printout of the email from the travel agent that passes for a ticket these days. I was given a boarding pass and told to hurry to the gate. I did so and got all the way through the process, including showing my passport and boarding pass at the gate, and onto the seat that was allocated.

After taking my seat someone else boarded the flight and said I had their seat. We queried this with the cabin staff, and it turned out that I had been given the boarding pass of Wayne Smith, who had checked in online with no hold luggage. I should have been on the subsequent flight on the same route.

Initially I was told to depart the airplane, and that my luggage was not abroad. I insisted it was (I had a luggage tag), and after about 15 minutes (during which they held my passport) I was allowed to remain on the flight. So everything was fine in the end, but clearly could have gone wrong if I had not insisted that my luggage was on the plane.

If the process was human driven, I could see how such a mistake could happen, with someone seeing 2 names (though on different documents) and getting one incorrect identity. However at check in AND at the gate passports are scanned by computer, and the airlines have passport numbers to check that the right person is getting on the plane. I had assumed these systems were taken fairly seriously, as they are involved in the two of the governments hot topics, terrorism and immigration.

How does a major airline make such a mistake that could have serious security consequences as a result of an occurrence that must happen quite frequently (two people with names that can be reformed into a third persons name on a different flight)?