Vettel definitely isn't a driver that is generally susceptible to pressure. He did this this, but one mistake doesn't a rule make. As Hyper says, Fisi is much worse with his stupidly early defending, and I'm sure there are others that are even worse.
What we haven't seen (that I recall at least) is Vettel having to fight through the field after a mistake/poor qualifying/puncture etc. Would he be a Button, Schumi, Webber or Hamilton (on a good day
), or would he tend to throw it off or do something silly (Sutil, Hamilton on a bad day etc)? We don't know that yet, but it's probably the only un-answered question over Vettel, isn't it?