Union WP farm
Someone already posted this “exploit” in this forums and answer from arena net was this: “Thank you for your report. To prevent possible exploits from spreading, exploit reports will be removed from the forums. We kindly ask you to report possible exploits to the team by sending an email to exploits@arena.net. Your thread has been deleted.”
There is a thread in guildwars2guru about it too.
Hope it helps in your decision.