Heh, that sounds like something that happened to me recently. I was trying to nonrev to Amsterdam from Minneapolis on a flight that was overbooked by like 13. I actually did initially get a seat - but then the agent came on the airplane and pulled me off, said better luck next time. I decided to just hang around until the door was actually closed. Sure nuff, somebody who had checked in was nowhere to be found, there was one seat open - and I got it.