I don't think Petrov can be completly held accountable. Yea, sure he was behind the wheel but again we see the failings of DRS. If neither of those cars had DRS they would have known where to brake, what was the late breaking point. Alonso pushed that move because he was going to use the runoff come what may, that left Petrov with such massive closing speed to schuey that he had no chance. Sure, Petrov should have been wary of the effects of DRS coming into that corner, when you see the closing speed, The back of shuey's car travelling about 50mph whilst doing his own racing, only a 100 metres in front of a car just starting to brake from 200mph being outsighted by Alonso who knew he was going to go cruising into the runoff anyway.
Just another example of how these cars are just not designed to run together. There has to come a time when the technology is actually detrimental to racing. and I think we passed that years ago. Sure these cars are at the pinnacle of motor racing. They do things that no other car can do. But at the end of the day, If I want to see the fastest cars on earth go point to point, I'll head to Santa Pod for the day. Now, when I want to see Team racing, I'll watch Aussie V8's. Big, Low DF, Skilled drivers and some of the closest racing you'll see on the planet.