Since this happened to one of my sisters TODAY, I thought I had better post this, as most people are not aware that electronic pickpocketing tech exists. Aluminum foil and such protection isn't good enough. Have to disable and/or block that damn RFID shit.
You can buy aluminium wallets now to block the signal being picked up while still in your pocket. Just make sure nobody is too close when you whip it out. ;-)
However, they don't work if a criminal amps up power of a RFID reader and boosts antenna, easy with free online instructions on how to do it, they can still penetrate these passive shielding or blocking devices (wallets / credit card sleeves & aluminium cases) by what is called a brute force attack. These passive devices may limit the distance you can get skimmed from at best but you will still be skimmed if this happens.
Actual organised criminals (not just opportunist) can amp up a RFID readers power and boost the antenna and just by a brute force attack will still penetrate these passive RFID blocking or shielding wallets / purses, credit card sleeves or aluminium cases. At the best they may limit the distance you could get skimmed but you can still get your data skimmed. After doing the research on this to protect credit cards and passport go for an active solution like armourcard which is an electronic jamming product. You can use 'tap & go' every day and will really like the convenience of it but rest assured that at least you have secured your stuff to the best of your ability.
Just buy an Armourcard is electronically jams the frequency these cards & passport communicate over, best protection ever. http://www.armourcard.com.au/
Another thing to beware of...
Have you been in a shopping mall or store that has a contest or give away, where you fill out an entry form for a free car, vacation or cash at a stand alone table or counter top? This was a scam reported at a local mall, the RFID reader, was hidden in the counter top so when people walked up to fill out the slip or read the sign, they read your credit card and stole your details. Shield your cards. Be aware and BEWARE.