Ummm...yes but Trevor Rees-Jones survived and the other three didn't, which is the point that I and Eddie, and others are saying.
No one is denying that all the other factors are implicit on why the car crashed...paps, speed, drunkenness.
But the main reason she died was because she wasn't wearing her seat belt. If she had have had it on, then there is a very good chance she would have survived.
She died from a massive head injury, caused by her hitting something, or someone in front of her. A seat belt would have prevented that happening.
I realise, by the way, that you are aware of all this !