Well it happened again. Someone tried to use my debit card to make charges I didn't authorize and no it wasn't Lady Allclick. She learned her lesson well after I prosecuted to the full extent of the law (kidding, of course!).
I checked my bank last week and while skimming through noticed a charge of $1.00 to "APL*ITUNES 866-712-7753 CA". It was still "Pre-AUTH" so it hadn't completed yet but I knew something wasn't right. I called my local bank but as it was 4:31 they were closed and there was no-one available to speak. In the end I called the stolen/lost hotline and they canceled the card. Even the $1.00 didn't go through so that was great, but for the second time in two years I'm waiting for a new debit card to arrive.
I decided to report the card after doing a little research. It turns out that lots of people have fallen victim to this. Some with or without itunes accounts. Frighteningly, many people reported that when they had alerted Apple to the fact that someone had made fraudulent itunes purchases on their account Apple did jack squat and state that they do not refund any "authorized purchases". Some folks had hundreds of dollars of charges. Another guy had his itunes connected to his paypal and they were able to draw $4999 out of his bank without a red flag. Apparently in the small print it says that by linking the accounts you agree that up to $5000 can be made in purchases without letting the individual know.
From reading lots of comments it seems that the scam works by someone guessing your debit card number. Most banks use sequential numbering so once they have one debit card they can guess at the next number in the sequence. Then when they think they have the details they try the $1.00 purchase...if that goes through they go to town and rack up the big bucks, so check your bank statements often.