OK, first im sorry for my bad english i do my best if anyone can correct me i ll copy paste my message on a proper english.
Ok now i will explain how this "trick / exploit " work
Step 1 : What you need.
- A friend/buyer who want a character from you
- The friend / buyer need a battlenet account
------ That's all
Step 2- I explain how its work
1. YOu have the charactere on your account no-battlenet merged
2. you giving the information of your account to your friend and he merge your account to his battlenet account.
3. he transfere the charactere he want on his own account ( you doesnt need full info if u do it on the same battle net account )
4. You call blizard/hotline and said "omg my account is merged wtf wtf ???"rickroll"
5. They will unmerge your account and dont give you back the chara if u doesnt ask
6. profit ?
I have test this myself on a EU realm and this work.