Hacking RFID tags
News.com is reporting that Lukas Grunwald of DN-Systems Enterprise Solutions GmbH has written a program called RFDump that allows someone to access and edit the metadata of an RFID tag.

Coupled with a handheld device, the software could allow a hacker to mark down the price of an expensive item, purchase age-restricted items and generally wreak havoc on a retailer's RFID system.

Even with these vulnerabilities (which exist in various forms for most technologies), I still think RFID is going to be huge win for retailers and consumers (even more so if I can discount big ticket items with my PDA).