So you are worried blizzard will "track" you down because you sold the gold?
The one and only thing they will do ( No I cannot confirm this, but from my experiences and what ive heard ) All they will do is to bann your account.
And btw
I talked to paypal yesterday, and they said. Unless blizzard or anyone else has a court order to get information from your paypal. Paypal will not give out any information.
So if blizzard really cared about scamming in game they would surely allready tryed to catch the gold companies by court orders.
I have no actuall evidence then that I called paypal. the rest is just what my experiences say.
and if there is any1 here that knows better please do share