Bad software
Anybody that has taken a flight in the last year or so will know that check-in is increasingly being handled by touch-screen computers.
So when 16 of us flew from Birmingham to Amsterdam last weekend for my brother’s birthday, you can imagine my surprise to get 2 boarding cards. It seems that whilst I was busily prodding away at “yes, I packed my own bag” etc, one of my brother’s mates helpfully decided to check me in as well.
So the system had happily checked me in twice and allocated me 2 different seats. Of course I went upto a member of staff and got them to cancel one of the seats, but it did occur to me that it could quite easily have caused a lot of confusion and delayed the flight. The plane was full, had I not known about the second boarding card it would either have had to choose a seat for me (but then I could confuse the cabin staff by sitting in the wrong seat and having a valid boarding card for it) or it would have had to refuse to check-in the last passenger due to having no seats left.
If they haven’t tested it for something as simple as checking in twice, it makes you wonder what they have tested it for!