Yesterday, I boarded a 757 at SFO headed for EWR. The reader buzzed. The (unfriendly) GA just tore my BP manually and gave me the stub, with a huff. She couldn't be bothered to check why my BP buzzed.
On the plane, someone was in my seat 2A. Her BP said BWI, not EWR, so I smiled and said, "ma'am, I think you've boarded the wrong plane - this one's going to Newark." Many people in F exclaimed "What, this plane is going to Newark?!? I'm going to Baltimore!".
Well, needless to say, I was on the wrong plane, and that's why it buzzed! Yes, I'm an idiot! Just needed to share!