Originally Posted by
UKtravelbear
VS has an algorithm to determine whom it op-ups and it includes things like status, previous flight history and the fare bucket your current ticket is in.
I agree with everything else you've said, but the algorithm part I dispute. It's a very manual process that requires human intervention. Status, Fare Bucket, BCN, Single traveller are all factors in the picking process, that I do know. I am fairly sure that BCN and Fare Bucket are the main two trump factors in the process.
That being said, if you have been selected you will know when you get to the gate as you will get a magic beep, although this also happens with standard seat moves. If you're using a mobile boarding pass, you'll see the change reflected there before you get to the gate if you keep refreshing it.