Fatal accident at F2 races

http://www.motorsport-magazin.com/…/…icht-trauer-um-f2-talent.html For years, steel ropes on the tires are supposed to prevent flying away, and yet it happens again and again in the formula classes. Why? Are the ropes undersized, the forces far too high and not predictable, or is it just bad luck. Even in the F1 tires fly again and again after a hard crash, sometimes even with suspension. Is this really not more efective to prevent, what do you think? G Rice