Originally Posted by
MSPeconomist
Now, however, with real time inventory sales, it should be easy to code availability as either 3 F or 3 Y, with the understanding that when a seat is sold, inventory in both cabin class buckets will be reduced. The odds of a simultaneous sale of more than three seats would seem to be minuscule and even if it would happen, DL would still win after paying for VDB(s) if necessary since the fares what are being sold are so high.
Simultaneous sales are impossible*. All final reservations/ticketing for pretty much every major airline still goes through an ACID-complaint database (which, in simple terms, means that the database guarantees that a 'double entry' so to speak is impossible). It's the same reason why - no matter how fast you click and how low latency your internet connection(s) are - you can't buy two low fare class tickets when only one is left in that cheap fare class.
* barring an egregious IT mistake