Very true, I can speak from experience. I 'went off' on a country lane during a road rally in 1971. For the Cheshire PlainZ boys it was a 'white' at Wincle near Bosley. It was a very deceptive corner hidden in a 'dip' . I put my Hillman Imp on it's side and when I got out I noticed a trashed Anglia hidden behind a bank. My navigator ran up the road to the previous 'control' and got the marshal to 'hold' the cars. After sorting my car out and parking it near the Anglia we gave the all clear and guess what - the very next car (a mini) rolled! I can still see it in my mind now sliding upside down wearing the tops of the wings away.
I should have warned him just like the Porshe drive should have.