I don't see how this is any different from selling logins, trojan logs or other data. Sure the seller can sell the cardable shop to somebody else or recieve a shop thats dead but its up to the buyer to take the propper precautions before buying.
Escrow, Feedback from other people and common sense. Over escrow just tell the seller to send the login to the most recent email used to make a succesfull purchase that has been shipped.
forbid it. if everybody will share cardable sites, everybody will try to rip them off with cvv, so they will soon improve their security. and we all f*cked up..