Is there a reason why you are allowed to buy back?
Change your mind, don't get the value you were looking for, or were looking to get a player to replace your listed player and fail so you buy them back. Those are just a few off the top of my head.
You do pay a price to buy your player back in agent fees, both in the actual cost and the reset to a higher agent fee percentage for re-listing.
The example is presented as how teams might be able to take advantage (maybe even cheat) by using the buy back policy. If anything this seems to be more of an issue with policy on collaborating/cheating then it is an issue with buying back players you transfer list.
"Well, no ones gonna top that." - http://tinyurl.com/noigttt