Unfair advantage is just that, an unfair advantage. Why? Because of the fact that the other person/people may not have knowledge of the manipulation of such an exploit, OR acknowledge said manipulation, but refuse to engage in the activity because of the former.

Now, if all the players within a single match know that the other players can and will make use of such an exploit, could you consider it cheating then? Cheating is basically deception, or being dishonest. How can the others be deceived, though, if they KNOW and INTEND to make use of the manipulation of this exploit, and that they know that everyone else will use it as well? The obvious problem with this logic is that, more often than not, there is at least one person who does not know of the exploit or how to use it.

When such is the case (and it almost always is, except within rare instances), this gives the "cheater" the unfair advantage. People making use of ANY such exploit know that they are giving themselves an advantage, fair or otherwise. Why else would they do it? Because they know it tips the match in their favor, thereby highlighting the word "cheating."

I'm going to have to agree with ShadowMarth, here.