Unexpected Upgrades - How do they work?

[kempvet]

A couple of times I have been sitting in the SIN Q Lounge and my name has been called - found out that I have been upgraded to Premium Economy. How come?
Is the answer that economy has been overbooked and because I was in the lounge they upgraded me, I was only bronze at the time. Could it be that with only 100 SCs I was one of the highest qualified on the flght?
Also early to the airport, end up in premium economy, is it the same thing, economy overbooked, therefore first come first serve with the upgrade.
In a few weeks I will be platinum, is this senario likely to happen - upgraded even when there are spare seats in economy. Recently was behind a CL in LAX, he was upgraded into first, seem surprised as he never expected it as he was travelling with his wife in business. Do upgrades happen without asking when the plane is not full, or are the decisions internal policy with Qantas and not revealed?

 

[simongr]

Firstly they don't work ... for me! 120+ upgradeable flights and 1 upgrade...

The aircraft doesn't need to be full - for example if they are trying to seat a couple or family together and your seat might be the only way to make it happen.

 

[richie9x]

If you receive a free upgrade it is hard to know why you received as often the airline won't tell you. The most common type is the opup (operational upgrade) where they need to make room in economy by moving people forward. This can be due to overbooking, an equipment change, faulty seats or the need to accommodate passengers from other delayed or canceled flights.

It also seems that sometimes if you get mucked around a lot by Qantas they will give you a free upgrade. It has to be quick a major stuff up for Qantas to give you such an upgrade. Also late last year Qantas was giving out free upgrades on some domestic routes to WPs and CLs. This was as part of the apology for the grounding.

It is also possible they give out sampler upgrades to select people. So that you get a taste of the higher class and with the aim of getting you to book it next trip. Other airlines have been known to do that. Hard to know if Qantas does this, but if they do it is fairly rare.

So in summary if you get a free upgrade it is hard to know the real reason behind it. Don't expect to get one, but if you do then great.