Originally Posted by daOldMan

If you are positive space, you are 100% guaranteed a seat on that airplane, unless the flight cancels.

People that buy tickets are NOT positive space. Flights are oversold all the time, and purchased tickets do not guarantee a seat on a flight.

There are very few reasons that someone is positive space. It means that the company needs you to be on that flight. A DH'ing crew is positive space. A DH crew will bump paying passengers off of a flight.