You don’t, really. Whoever is checked in first gets the seat. The second person will be questioned, and hopefully it will be cleared up. With the number of flig

You don’t, really. Whoever is checked in first gets the seat. The second person will be questioned, and hopefully it will be cleared up. With the number of flights in and out of the US each day, it’s bound to happen unless the false positive rate is extremely low, which would only be possible through an extremely invasive cataloguing of photographs beyond those taken for DMV and Passport photos.