The issue is that by not having enough fuel, you are disqualified. Hence its a major penalty. It is non sensical though, because IMO the disqualification should not be from the whole of qualifying. It should be just from Q3, because you have already beaten those eliminated in Q1 and Q2. It's certainly a very poorly written rule. But one they all knew about ...
Perhaps next year they'll change qualifying, to making all the cars start each Q, with a set amount of fuel. Hence the cars might stay out and run their fuel down. It would be more exciting IMO. And perhaps, more easy to ascertain about fuel left ... but somehow, they'd have to ensure a team did put all the fuel in stipulated by the FIA. Putting less in, would favour the car, because it would be lighter with fresher tyres.
Nothing's simple in F1 ...
Qualifying is one session. Q1, Q2 and Q3 do not constitute separate sessions. I don't think there is a mechanism for disqualifying a driver from one of those. He can have times excluded - which means he would start 10th, rather than 11th if he was removed from Q3.
It is a breech of the technical regulations, and thus the stewards could possibly disqualify the driver/car from the event.
The interesting wording in the Autosport report is this:
However, the stewards have allowed Vettel to start the race from the back of the grid.
In other words, by disqualifying Vettel from qualifying they could opt to not let him race.
Edited by Wuzak, 04 November 2012 - 09:29.