Interesting that many are so skeptical.
First off, do you really think this is the poster's first post on FT? If it was me I surely would have created a new handle to make this post. For all we know it's a long-time member.
Secondly, it says the airlines first contacted the buyer. I would suspect even if the seller was fairly careful not to include identifying info in the eBay auction, the buyer of the miles would clue the airline in as to who and how they paid.
Finally, if it was an airline rep I would think they would have written that the person's account had been permanently closed. This is far less punishment than I thought happened in these cases.