Originally Posted by Stripe

I once successfully boarded an AA flight in AUS bound for LAX when my ticket was for a flight to DFW boarding at the same time at the adjacent gate. My BP beeped correctly and the GA noticed nothing. I became suspicious when I saw 3x3 seating and I thought I was flying on an MD-80. Fortunately someone was in my seat and I quickly determined I was on the wrong plane and was able to deplane before they shut the door. No one was able to explain why I was able to get on. And my BP also worked fine on the flight I was actually booked on.