Hey there OwnedCore!
First of my real contribution here, so here we go!
Basically this is what happened to me, I have my own account, that I got all my stuff : my main, my gold, my achievements and so on;
this account is in very good standing (never been banned and stuff like that) but I wasn't happy with it because I missed a lot of the game content ie Vanilla and TBC, and I wanted some FoSs from them, so I bought an elite SoR account from one of the popular sellers here and attached it to my main account.
It had 3 Feats and it had some good vanity gear as well and I was happy with it.
But then I got a ban for "selling gold" from that account and after a live chat with the GM he noticed different names and locked that account and removed it from my original battle net.
I was pissed but then I noticed that under my achievements there still are achievements from the SoR account even though it is no longer on the same Battle.net!
Then I wanted to try something else:
I have an old account that is ready for SoR and attachment but it belongs to my best friend. Basically I am going to attach the SoR to my main battle.net and then my friend will attempt to recover that account, when it gets removed hopefully the account will have my achievements, mounts and so on
I know I know, it sais [NO THEORIES] but, this is just the other part of the exploit that I couldn't test out because i can't access my first SoR account (the removed one)
Tldr version:
If you got a SoR account attached with some achies and it gets removed, you won't lose achies on both accounts and therefor they will be duped.