People have been concerned about RFID chips for many years now, and not just in credit cards. All US passports issued after 2006 have RFID chips that track your photo and information. Metro cards have RFID chips for quick swiping, and dogs are implanted with RFID chips for tracking.
RFID chips work by using radio waves to communicate. The object, such as a credit card, contains an RFID tag with information, and an RFID reader uses radio waves to read the information off that tag.
The key is that RFID chips have tiny electromagnetic fields, which is what makes it possible to read one without having to “initiate” communications. The RFID reader just needs to be close enough to get within the field.
That’s why, in theory, somebody could scan a card through your pocket. And yes, people in the real world have been scanned like this. Check out this anecdote on Reddit to see what kind of headache can result from RFID hackers.
Fortunately, radio waves are relatively easy to interrupt and block, and that’s how an RFID-blocking wallet works. They encase your credit cards in a material that interferes with radio waves. If the wallet is properly constructed as a Faraday cage, it will block all electromagnetic fields and prevent communication between your cards and RFID scanners.
But do YOU actually need an RFID-blocking wallet? Probably not. If your credit cards don’t have RFID chips, then obviously you don’t need one. And even if you do have RFID-chipped cards, the chance of being maliciously scanned is exceedingly low—less than 1 percent according to some.
On the other hand, the possibility is always there and the chance is non-zero.