How I though of this.
Well, I was doing the typical turtle mount scam to get myself some gold. It was on a dedicated scamming account but I did get an interesting reply which got me thinking about a specific theory.
How this could apply to scamming.
Say I was scamming on Account A. I change my IP. I then proceed to put a specific item on the AH for amount of gold I scammed so I can later pick i up on my legit Account. I proceed to change my IP address and log onto the same server and I buy said Item. IP change once again. I log onto my main and I get that gold and am happy. All blizzard tracking aside, there is no link between those 2 accounts and they should not be linked in any way right? WRONG!
Important stuff starts here.
What if Blizzard uses a Hardware ID? Let's say that anytime you log into wow from any account that same ID is sent. That would definitely link the two accounts and could lead to a ban since they were on different IP Addresses but the Same Hardware ID.
Conclusion.
There is no specific reason to know this but just a heads up to scammers and hackers. There have been many cases of people banned on multiple accounts when only one was gliding. Like I said, Just a thought.