jigjag re chess cheating
Technically that cheating grandmaster was banned only from tournaments under the auspices of the World Chess Federation (FIDE - Federation Internationale d'Echecs). He subsequently entered a non-FIDE tournament under a new name and played a couple of rounds. However, he was rumbled and is so 'persona non grata' that he was excluded. He was the one photographed in a toilet cubicle consulting a chess analysis app on his phone.
Now that competitive chess has to be nearly all online, cheating is a real problem, though the various chess platforms are very good at detecting it. I have played 28,000 blitz games online since 2001 (5 minutes each for all your moves) and if the odd opponent has cheated, it doesn't bother me - there is nothing at stake except your online rating. Bridge cheats online have been named and shamed too - unbelievable to me when there is usually no money in either game online, especially for amateurs. They have managed to run pro tournaments with players constantly visible on webcams.
I like the clue writing competitions here because they are not susceptible to cheating.