When you visit online stores that take Bitcoins, like
www.bitcoinstore.com, at the end of the checkout, you are presented with a one-time-use bitcoin address that is valid for 15 minutes.
What happens if I send money to that address after the link has expired (using a Bitcoin wallet like Bitcoin-QT)? Will the transaction not go through, or will my Bitcoins disappear, or will they end up at the merchant anyway?