Title says all. How do they? Is their some kind of software/API that allows a business to see a customer has performed their transaction so they wouldn't need to wait a ridiculously long amount of time?
My best assumption is they would be able to look it up through blockchain.
Using Bitcoin to buy a latte at Starbucks is like using gold to buy groceries. Retail spending is the wrong application for a store of wealth.
XCN has reimplemented the blockchain in such a way that safe zero-confirmation transactions are possible:
Cryptonite is the first altcoin to feature withdrawal limits, allowing users to set a limit on how many coins they can send from an address in one block. This is useful because it helps to prevent double spending and increases confidence in low-confirmation transactions.
If a merchant can see that the withdrawal limit on an address prevents it from being emptied in a small number of blocks they can have much more confidence in any transactions sent to them from that address, even without any confirmations at all. So the main advantage of withdrawal limits is that 0-confirmation transactions become safer in the right conditions.https://bitcointalk.org/index.php?topic=713538.0