Ferrari had sought "clarification" over the move, which appeared to take place under a flashing yellow light, when overtaking is banned.
Had their suspicions been upheld, Vettel would have incurred a 20-second penalty and - crucially - the sixth-place finish which just clinched him the Drivers' Championship crown. Instead that honour would have gone to Fernando Alonso, of Ferrari.
Of course, the last thing true F1 enthusiasts wanted was for the 2012 Drivers' Championship to be decided on the legal circuit rather than a tarmac one.
It was a swift and sensible decision which killed a potentially embarrassing row before it could take hold. So three cheers for the FIA!
Well, up to a point.
You see, I am not an F1 purist. I am an F1 impurist, one of those weird and hateful individuals known as a "casual fan".
And, like many other casual fans, I was rather hoping Ferrari would forge ahead with a legal challenge on Vettel.
I took this view not because I genuinely believed Vettel did anything wrong. Being honest, I simply did not know if he was guilty or not.
Yes, the internet was awash with footage of the young German appearing to overtake while the warning light was on - but even I knew that is not enough to cast judgement without being viewed in its full context.
Nor did I take my hard line because I have any personal axe to grind against Vettel. On the contrary, he appears to be that most unusual of things: a serial winner who is also a likeable, charismatic and fully-rounded human being. Such rarities should be treasured.
And, of course, I knew that Ferrari trying to win a sporting battle in the courtroom would be deeply unpopular among some fans.
To stickle over a minor infringement would be surely seen as petty and unsporting by all but the most ardent of Ferrari and Alonso loyalists.
To do so after Ferrari themselves had already manipulated the rules - legally but cynically - by deliberately breaking the gearbox seal of Felipe Massa's car to bump Alonso up the grid during the United States Grand Prix in Texas, would make it even harder to stomach.
But, to my mind, these were not reasons for Ferrari to be coy about launching a legal challenge. They were precisely why it should happen.
More than almost any other sport, Formula One needs its ongoing soap opera of heroes and villains to appeal to a mass audience. We casual fans need a scarlet lady and, for as long as I can remember, Ferrari has been the Alexis Carrington, the antagonist of the popular 1980s US soap opera Dynasty, of F1: haughty, ruthless, conniving and amoral.
From its infamous and unsporting team orders, in which "junior" drivers such as Rubens Barichello and Massa are ordered to let golden boys like Michael Schumacher and Alonso past, to its past strikes and threats to leave F1 and join American Indycar, Ferrari is just as famous for its machinations as its machines.
So they should have tried their luck and sent in the lawyers: the more the merrier. They should have dressed them in scarlet suits and, if they won, celebrated on the steps of FIA headquarters.
And if they lost? It did not really matter, because the objective would already have been achieved: to cement their position as the "Senor Nasty" of rmotorsport and to keep their sport on the public's lips during those long months between November and March.
To purist fans who would have moaned that the magic of Sunday's thrilling finale would have been demolished by a legal challenge, I say this: no it would not.
If you witnessed the excitement of Interlagos, when Vettel snatched his crown by a mere three points, then it is yours. You own that moment, which is now sealed in the past. No lawyers in the world, no matter how expensive they are, can travel back in time and take it from you.
However, for a guarantee of more excitement on the first day of the 2013 season, when the wronged hero and ruthless villain would have squared up on the grid at Melbourne, a courtroom battle would have been just the ticket.
Dry legal proceedings may lack the raw excitement of a glorious day at the track, but they are more than enough fuel to keep the glorious potboiler that is F1 simmering nicely over winter.
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