Late to this particular party, but on a similar note...

Boarded the DLR to LCY last Friday for the 1420 EDI flight. Train was packed, standing room only, but a chap in one of the "driving" seats was occupying the full width with his personage and luggage. By Shadwell, he grudgingly gave up half his double seat to a mum and baby. All very lovely.

Imagine my surprise on boarding the E170 to find said gentleman in possession of my seat, 1C, with his belongings scattered in 1D. Obviously, a serial double-bagger, I thought.

I started putting my bags into the overhead and mentioned that I was in 1C and would be taking my seat very soon, pointing to the aisle space. "No, I'm in 1D, it's the same seat I had on the way down", he replied. "Yes, and 1D is the window seat", I responded.

I think he was on the point of demanding to see my BP but decided not to, and made a great show of stuffing his bag into the overhead and moving his newspapers and files to allow him to sit in 1D, all the time accompanied by under-the-breath effing and jeffing.

When I sat down he again reiterated that he was in 1D on the way down and that it was on the aisle. All I can think is that he was on an RJ where 1D is indeed on the aisle. I didn't bother enlightening the ignoramus.