It's a type of fraud that happens frequently: Criminals attach devices to cash machines that record the account data stored on the magnetic stripe on the back of the card, a practice known as skimming. The card's PIN (Personal Identification Number) can be spied with a secret camera or a fake number pad overlay.

As a reporter who covers computer security and fraud, I'm aware how easy it is to become a victim of skimming and how difficult it is to defend against. But I've always been more worried about how I'd get the money back than about actually being skimmed, since banks seem less inclined these days to assume liability.

Most banks in the U.K. and Australia would like you to believe they always refund stolen funds. But the reality is that a bank can easily deny a refund based on flimsy reasoning that leaves consumers with little recourse other than going to court.

Commonwealth Bank of Australia is one of the major banks in the country. It that it will "guarantee to refund any fraudulent transactions that take place within five days from when you report the incident to us."

In my case, things didn't go so smoothly.