What is Cheating?

There has been a lot of media in the last day or two about the Australian Cricket team cheating in a test match in South Africa. The specific cheating was something called 'ball tampering', which is to illegally affect the surface of the ball in order to create an advantage when bowling. I don't know for a fact, but I'm sure that the justification for doing this would have been: "We are sure our opponent is doing the same, so we are only doing it in order to create a fair competition." Now, this is not completely unreasonable. In fact, one of their opponents has been twice suspended for doing exactly the same thing. What's more, there were suspicions Australia were tampering with the ball in their recent series against England , but surely this is just evening things up from the series in 2005 where England tampered with the the ball . Right? And then there were the complaints by the Australians earlier in the series that the on-ground micro