Consider this hypothetical scenario.
Today you receive a legitimate in-game message from Blizzard. The message states that you (and only you) are being given an opportunity - now - to equip a future expansion's T15 class set.
In the interests of clarity, this is a PvE rather than PvP/arena set, and you will not be eligible to participate in battlegrounds with this gear equipped.
If you accept this offer, the new items will remain with your character for one month. After that period lapses, they will disappear and be replaced either by your original gear or whatever upgrades to your original gear you have accrued in the interim.
This proposal presents obvious pros and cons, depending upon your approach to the game and your reasons for playing.
Would you accept?