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Some of the new credit cards have RFID readable chips embeddded in the card that can be read by someone passing a reader within a few inches of your card - say while you are standing in line. Tinfoil may or may not work, depending on the frerquency used for the card. Best bet is to buy sliop covers specifically designed to block RFID reading - Amazon has a set of 10 for (as I remember) about $20 or so. If you travel, you might also think about a passport slip case, because the new passport have RFID biometric and ID data embedded in them - takes a different size and type of cover, because frequency is different.
Answered 11 months ago