I don't think it's fair to call this an exploit, rather it is a bug due to poor coding that not many people know about the true buff (which Mindark hasn't ever actually fixed even though they knew the "buff" didn't show up on your buff bar). It doesn't require any special action from a player to utilize other than buying a pet and activating it's buff.
You can disagree if you like, but it is use of a bugged item for financial advantage. It does not matter who had access to it in your theory. Most people didn't know about it other than apparently PK socs, that use it regularly for other means AND have a list of other complaints against, and those who are competing in events.
Exploit is an exploit is an exploit. End of story.