Let us go back to 1983 world cup! In that tournament until finals, West indies thrashed every other team by good margins, isn't? In the finals, WI chasing 183, were something like 50/2? Suddenly it was 68/6? You might say brilliant bowling by India etc. But the odds of Indian victory before that match was something like 100-1 (i.e. out of 100 people 99 would have said WI victory)? Now how are you going to prove that there was no betting in that match?