Pitfalls reported in Jonathan Schwartz article "Researchers see privacy pitfalls in no-swipe credit cards" are interesting but even encryption won't stop bad guys if signals are repeated and bridged, in effect allowing a no-swipe card in your wallet to be used in realtime at no-swipe card reader thousands of miles away. An engineer's solutions to this problem could get rather complicated, requiring noisy cards and multi-phase transactions. A simpleton's solution is to require use of anti-swipe wallets or sheaths. But then what's the point of no-swipe if you have to take it out of your wallet to use it?