I buy Darkcoins from a party that is KYC compliant, and transfer them to my wallet address A. Now the address A can be linked to me.

Next I put them through the Darksend mixing process, and now instead of having coins in address A, I have coins in addresses B1, ..., B10 for example. Then I proceed to spend the money in address B5 by sending it to ya public donation address of WikiLeaks.

Later when you find out she's been doing business you get angry and try to find out who's been paying her. You import private key of the address B5, and then what?