Even though I know he is likely being sarcastic, I think that Mr. Future hits on a very interesting consideration that reflects on how our society defines "earning" something. It seems to me that one of the core foundations of capitalistic society is that there are 3 ways to justly achieve a higher income or status: hard work, luck, and assumption of risk. The first two are obvious but what of "assumption of risk?"
Ingrained in our notion of "success" is the fact that one need not necessarily be the smartest or hardest working to achieve it. Sometimes the successful person is just the person with the "biggest stones" who puts the most on the line in hopes of achieving the highest award (IE- putting your life savings on the line to invest in a risky venture that takes off). Likewise, when someone makes the decision to cheat on the LSAT, they are making a huge gamble in hopes of a (likely) moderate increase in score. They put it all in and take a risk that most of us would never dream of: banking their entire (legal) future on the fact that they will not get caught. Considering the the odds are heavily stacked against them, they are taking a perilous bet and it could be argued that they have technically "earned" their higher score by virtue of being willing to take that gamble and risk losing out on LS altogether.
My favorite analogy for this is the guy on the motorcycle that weaves in and out of a traffic jam, conceivably arriving at his destination sooner than everyone else. This angers a great deal of people, as they feel that it is "unfair" that he should arrive sooner than them at his destination and they should have to wait. In reality, I submit that he is "earning" his early arrival by assuming a litany of potential consequences. These include expensive traffic tickets, or simply being splattered all over the pavement. This avenue of "unfairness" is available to everyone but most choose not to assume that risk- a choice on both sides of the issue.
While none of this really affects the issue of whether to "tell" on someone who is cheating (still your choice on whether to bring the risk of their venture down upon them), to me it raises some interesting considerations as to the ethics of cheating in a capitalistic society. I would argue that cheating is neither just nor injust- simply a different way of playing the game. Likewise, getting caught is neither just nor injust, but merely the laws of probability paying a visit to someone who made a lofty gamble. Much like with short-term winners at poker, those laws of probability seemingly would assure that someone who makes a lifestyle of cheating will get caught eventually. A gamble that they choose and a consequence that they will have to live with.