Actually, May is not the only update that brought hackers. The gold duping was around Roughly around werewolf update, perhaps one or two before. (Publicly, that is.)
I expect the fact that it's premium and so many people illegally obtained it, crashing the servers (as gold duping is likely ALREADY rough on their servers), not to mention the actual economical loss, they probably got pissed off and just upped security.
At any rate, this is exactly why we DON'T interact with Koreans. And can't stand the numskulls who do.
