Which worlds can you not world Xfer into?

Because new worlds typically had all sorts of events only for them, like 3 weeks of continuous 2x, or a special bandana.
Nexon didn't want people starting a character there, leveling it fast and getting whatever special gifts, and then transferring out and leaving the world dead.

Leaving the world dead will happened when events are over, there is so many 2x exp events now in other worlds aswell so it wouldnt matter if they made new chars there and left afterwards.
I can see it being a problem pre big bang, not so much after big bang.