Cheating can be a real issue when it comes to online games, normally java or shockwave based. Some people have learnt (or already knew) how to hack/break in to the games and register impossibly high scores.
The images below are from a lastminute competition that ran some years ago, but it demonstrates that cheating can and does occur. In this case, lastminute acted swiftly to make sure their competition was played fair and square and all persons found to be cheating were disqualified from the competition.
