Every knows that the BGs are chain-disconnecting people during large fights like on Drek'Thar, or upon exit. What some people don't realize is that this is a rollback as well. You can try moving items around your bag and wait for a crash, all items go back to their original position.
What you can do to dupe is this... Queue AV at exactly the same time with a friend / other account. Wait for queue to pop, if its the same AV, enter, else try again. Trade money from account X to account Y. Account Y will log out so it does not crash and receive a roll back. Account X will sit in the BG until the server disconnects him. It happens VERY often atm probably due to the large number of players in the BG and once your character is rolled back, the dupe happens.
To re-iterate:
1) Have 2 accounts X and Y queue AV at the same time
2) Join AV
3) Give items/gold from X to Y.
4) Y logs out.
5) X waits for disconnect + rollback.
Enjoy, not my fault if you get banned / whatever.