Several players have been caught cheating in the past. They have used a variety of technologies to cheat. Of course it started with a pocket PDA and then consult an engine in the toilet. Cheaters with a bit more high tech stuff have also been caught. I'm sure there are still a lot of cheaters out there who have not been caught and will not be caught. You need to have a decent level of chess if you don't want to get caught, and understand which moves a good player would make and which moves a computer would make.
I'm lack of knowledge about the history about chess tournaments but knowing that it happens, in every sport there were always those exploitation that's being done by these athletes. Too bad that these have to do it because they probably know that they can't compete.
Why you need to think of being caught? You don't even want to get involve into cheating, the fun and intelligence that's involved in this game is going to be gone if someone thinks of doing it.
This is true. In sports, cheating shouldn't even be an option because the sports like chess is all about strategy, techniques, intelligence, and skills. The competition would be futile if they would even think about cheating when effort should be made, not some sort of tactics to just win, disregarding the process on how to get the winning title and prize.
Nowadays, it really isn't a secret that there are numerous ways to cheat. In almost every platform and games, there are cheats that are being made and sold. However, this just beats the essence. In addition, the cheating ways aren't even guaranteed so why bother. Instead of thinking that way, you can condition your mind and aim for winning by playing neat.