So at the cost of usability (for the cell user), wouldn't a product (or homemade solution: Hello, tin foil!) that blocks RFID/wifi signals wrapped around the ph

So at the cost of usability (for the cell user), wouldn't a product (or homemade solution: Hello, tin foil!) that blocks RFID/wifi signals wrapped around the phone also foil (ouch) this tracking? I'm thinking something like Blokket (http://howsyourrobot.com/2012/09/26/blokket-blocks-rfid-wifi-signals/ http://howsyourrobot.com/2012/09/26/blokket-blocks-rfid-wifi... - I have no direct knowledge of this product, BTW; just googled RFID/wifi blocking). Obviously this won't work for facial recognition, but I see that's discussed in other comments.