Right, first off I don't lie, this actually happened to me. Unfortunately, I don't know how to replicate it.
I am on holiday and I am currently playing WoW on a crap PC that can barely run it (all settings low) not to mention terrible internet (256k). I had just done Heroic Ramparts, hoping to get a Primal Nether or the last few heroic badges I needed to craft my Deathblow Goggles (High lvl engineering helm). We finished the instance, but I didn't get the nether. Fortunately I had 12 badges, so I went to Shattrath to buy the nether. I opened the window and right clicked the nether. Nothing happened. I figured I was lagging so I spam clicked the nether and some other crap. After about 5 minutes it caught up and the nether was bought. A second later I D/C'd and tried to login again to get the message 'World Server is Down'. I tried again and it logged in, but I was back in the Inn I had hearthed to after the instance. Turns out that everyone in Shat had got D/C and rolled back. I checked my inventory and was like 'wtfh4x'. I had the nether and still had all my badges.
Conditions under which this happened:
-12 badges
-15-20 minutes before server shutdown (Tuesday maintenance)
-WoW on lowest settings (Lag in major cities still)
-Slow internet
I am aware of various ways to make a server shutdown, many have been posted on this forum. I propose getting some friends to crash the server, and just before it happens buy something with badges. If you get a rollback, then it should work. If only this happens when I buy my epic flying mount
I cannot confirm this, and if you lose marks/get banned attempting to emulate this 'dupe' then that's not my problem.