Wildstar recently migrated players to one of two 'megaservers' themed around PvE and PVP, and following complaints that the PvP one has been a little too quiet, they've now been given a way to transfer between them. Players be able to make the switch in either direction, for free and for an indefinite time period, although the devs will be "keeping a close eye on things for any shenanigans or foul play".
Here's Carbine's reasoning in a bit more detail:
"For the time being, these transfers will remain open indefinitely, but we will be closely monitoring the situation and if we feel it necessary we will remove this service. Rest assured, we will ensure to give you appropriate notice if we do decide to shut these free transfers down, as well as an explanation as to why.
"We expect there will be some concerns about players using PvE servers to level up, without the dangers of a PvP server, and then transferring across once they reach max level, however we felt that ensuring the health and community of each server is more vital. We will be keeping a close eye on things for any shenanigans or foul play though."
If you're wondering what we thought of Wildstar, you should have a read of Phil's review. Spoiler: he liked it a lot.