I pondered this in this thread:
https://bitcointalk.org/index.php?topic=622253.msg6895575#msg6895575The system i was thinking about was a simple pull with 2factor auth.
Take a festival or holiday resort for instance,
Client arrives and charges up a QR wristband with BTC, pays for food/goods by showing QR to the merchant. Confirms the price of the goods and enters password/pin into the merchants scanner. goods paid/done.
It alleviates the need to carry cash, cards or phone & with the 2factor auth its as safe as using a CC.