Cheating

Cheating is a case where contestants attempt to rig the game for them to win in one way or another.

Sockpuppetry
Sockpuppetry occurs when a contestant (known as the sockpuppeteer) attempts to further their own game by entering a second account (known as a sockpuppet) into the game.

Another form of sockpuppetry occurs when a former contestant tries to enter a different account into another season, with the hopes of being able to play again, unbeknownst to everyone else.

Photoshopping
Photoshopping occurs when a contestant tries to digitally alter their challenge scores, making it look like they received a higher score than what they actually did.

Password Stealing
Password stealing is when one contestant obtains another contestant's password and play as them. This is considered cheating as another tribe mate is doing the work for a different tribe mate, which can unfairly help them win.

Helping With Scores
Helping with scores is considered cheating as another tribe mate is doing the work for a different tribe mate, which can unfairly help them win.

Glitch Exploiting
Glitch exploiting is when a contestant exploits a glitch in a flash game, which can unfairly help them win.

Trivia

 * Constance is the only known person, as of, who was caught cheating with proof.