Originally Posted by
ijgordon
what happens if, say, your 4pm flight gets delayed to 4:30pm and you don't show up to the gate until, say, 4:10pm. Could they have given your seat away?
I think the answer to this depends on if they know where you are. If you are delayed on an incoming flight, then they know where you are. They expect you to land and make a beeline to the connecting gate.
If you are just "somewhere" in the airport (lounge, restaurant, etc), then they don't know where you are. You may have left the airport entirely having pulled a hidden city ticket. Thus, it seems to me you have greater chances of your seat being given away if you are not at the gate when they begin to board or earlier.