ORLY? That's awesome!
I was going to suggest some sort of wallet so that the MoneyPak code could be acquired within minutes. So a green address solves that.
Though I have no idea how the blockchain.info mixer would be protected against a Finney attack though. This is a perfect example of what not to do. When mining, include a transaction that spends to self. If a block is solved, hold the block and the transaction without broadcasting. Send a 0/unconfirmed to a blockchain.info/wallet, then send payment to BTCPak through the mixer. Wait a few seconds until BTCPak shows payment and reveals the MoneyPak code. Then release the mined block which double spends the coin.
Profit.
I'm suspecting there must be something I'm overlooking with how you are notified by the mixer, or something.
I appreciate your concern against a finney attack. However, BlockChain.info takes precautions against these types of attacks: https://blockchain.info/wallet/send-anonymously
In any case, they assume zero-confirmation risk. If they get double-spent (or a finney attack), the input to the mixer would be invalid, not the output.
Although an attack is always possible, we haven't had an issue yet. Hopefully this continues