Why Some People Put These Credit Cards In the Microwave discusses anti-RFID measures:
A German group called FoeBud, which describes itself as a civil-rights group for the digital age, is featuring an array of RFID-busting products in the organization’s online store. Items include ‘deactivator nippers,’ which look remarkably like a common hole-punch, priced at about $7. The most popular item in the store has been a copper bracelet with a red light that blinks when it is near an RFID scanner, says Rena Tangens, FoeBud’s founder. The store claims to have sold about a thousand bracelets so far at about $18. ‘People think this is a cool gadget,’ Ms. Tangens says.