So the "exploit" is basically that since there weren't a lot of players early on, Warzones would end before they started because of not enough players. What was happening is that the few players in the Warzone were getting XP+rewards for a "win". Players were just constantly rejoining Warzones and reaping the rewards of XP. Apparently it is under investigation and is on BW's radar now. Official thread . I guess if anyone is in Early Access, give it a go. No word on if rollbacks of characters who used it are going to happen. Seems like a drastic oversight by BW. It's not even really a "exploit" and doesn't seem punishable since it is a game mechanic working as intended. The problem was that BW didn't allow enough people in early.
Want to do it? Here's how to take advantage of it:
1. Get Early Access
2. Identify the lowest population server as best you can.
3. Start a character on it.
4. Join a Warzone and hope that it ends because of not enough people. Receive XP
5. You should be able to get about 5-6 games done in 20 minutes.
6. If you actually have to play the games, it is not worth your time.
Good luck, BW is aware of this "exploit" so use with caution.
Also... You will need a low pop server for this to work effectively I believe.