Last month, I got on my DTW-LAS flight, and saw that the flight attendants fairly tanned, with great happy smiles. One of them were wearing a Lei (those Hawaiian flower necklace). I secretly hoped that I somehow got on the wrong plane and is heading to Hawaii instead of Vegas.... Unfortunately, after they closed the door and made the pre-flight announcement, they confirmed we were going to Las Vegas... However, thats not what this thread is about.

I've also seen multiple times people who got on the wrong flight and didn't find out until they're physically on the plane. I suspect the bar-code on the boarding pass doesn't contain a lot of information other than name and seat number... Perhaps someone smart enough to know bar-code can figure it out...

On a similar topic, I've sometimes scan the wrong boarding pass (unintentionally) to a flight (used the later connecting flight's boarding pass), and always got red-buzzed.