Bob, I think it was much later, in 2007-8, and more a Melbourne thing than Adelaide....
Schumi won the WC in 1994/5 In Adelaide for the final race Schumacher accidentally bumped into Damon Hill causing both to retire, and leaving Schumi as World Champion. At the time a lot of people claimed it was no accident, but a deliberate manoeuvre to ensure he won the title. I seem to recall that many people reckoned that Senna deliberately took out Prost at Suzuka in 1990 to win the WC, and that Prost intentionally caused a collision between them at Suzuka in 1989.
Like the Renault episode its all nonsense dreamed up by conspiracy theorists, and to think I once was one of them.
