According to MSNBC, Mastercard is planning to introduce RFID, touchless cards into the market beginning with four million cards in the next year. The coverage I've seen doesn't seem to address any of the security risks presented by this technology nor does it say how far away the readers need to be.
I know that I can get through the RFID locks in my office building by brushing my wallet near the sensor. It can read the proximity card through the leather of the wallet and through the cloth of my jacket. I've seen women hold their purses up to the sensor, which can apparently see through the layers of stuff that accumlate in an average purse. I'd think that a payment card reader would be able to read all the cards in my wallet if the sensor was strategically positioned. Interesting stuff, in any evetn .... See: MasterCard plans 4 million 'pay pass' cards - Tech News & Reviews - MSNBC.com.