Gotcha,gotcha 
Great minds think a like! haha.... I know I was trying to think how to autheticate against the blockchain also one thing I had thought of was a qr code when scanned in linked back to the txt ID or bitcoin payment address of the user ...only thing is if you wanted to transfer ownership not sure how that takes place.
The transfer of ownership would take place much like transactions with Bitcoins. That is, they would be recorded in the new blocks generated by miners (or "publishers"). Great minds think a like! haha.... I know I was trying to think how to autheticate against the blockchain also one thing I had thought of was a qr code when scanned in linked back to the txt ID or bitcoin payment address of the user ...only thing is if you wanted to transfer ownership not sure how that takes place.The payment for "ownership" would take place "outside" of the system. They could be paid for with cash, BTC, given away for free, or whatever.
The idea, in my system, is that any miner can become a publisher. Where as Bitcoin gives "coins" for mining, the idea I have would give the miner "rights to publish" to the system. There would be no maximum limit on how many cards could actually be published to the system.