My issue with this is that it's all circumstantial evidence. If you suspect someone of cheating but can't show it, then enact some anti-cheating provisions and move on. We can't have a rule of law based on just the suspicions of interested parties.
Of course we can rule out people by past cheating. Technology changes, it makes it easier to cheat but harder to hide cheating history (as most of the games between people at this time are online). Rules have to adapt to technology.
You can punish people for past cheating. But you can't say "he cheated before, therefore he's cheating now and that's why he won." I've seen that sentiment a bit too often.
