I think everyone here is trying to make this sound far more sinister than it really is. My guess it was laziness on the part of the ground staff. They probably got told "you need to bump two people off business" and they thought "ow geez that's going to be a hassle".
So the first customers arrive. They are asked if they would be willing to move to tomorrow's flight. (That's what I don't understand everyone is saying they weren't asked - but they were asked if they wanted to go to tomorrow). Customers say no tomorrow is not an option. So then the lazy customer service agent just says they have to be bumped so that they can get on with their day and not have to worry about going through this with every passenger. Certainly poor behaviour on behalf of the Qantas rep but not the conspiracy theory some are suggesting.
Sounds to to me that the underlying issue is that Qantas are generally pretty generous when this happens - we have heard stories of where passengers have been well looked after with a hotel for the night, presumably some allowance for food and incidentals and then often upgraded on the next day. The one place it falls down is when the passengers move to a lower class, it seems the refund of the fare is pretty unreasonable.
As as far as going to A Current Affair or the Courier Mail (someone was suggesting the front page no less!), you are kidding aren't you. Here we have this pretty well off couple (if they can afford $15k for airfares and do it reasonably often), who had a bad experience but for one it was reversed before the plane took off, they are then going to get a refund of which the amount is pure speculation at the moment, plus a $500 voucher, plus 50,000 points. I can understand why they would be annoyed, very annoyed, but let's keep this in perspective. (Also do you think media do overly negative articles about their biggest advertisers?)