There have been cheating scandals in top level chess, most notably in 2010 involving French top 100 player Sebastien Feller and in 2012 involving German GM Falko Bindrich.

These two scandals involved computer assistance. There are other forms of cheating, like throwing games, which are even harder to proof.

Illegal moves aren't an issue, but Kasparov allegedly violated the touch-move rule in a game against Judith Polgar.

There have been cheating scandals in top level chess, most notably in 2010 involving French top 100 player Sebastien Feller and in 2012 involving German GM Falko Bindrich.

These two scandals involved computer assistance. There are other forms of cheating, like throwing games, which are harder to prove.

Illegal moves aren't an issue, but Kasparov allegedly violated the touch-move rule in a game against Judith Polgar.