Wireless identity theft is a relatively new technique of gathering an individual’s personal information from RF-enabled cards carried on a person in their access control, credit, debit, or government issued identification cards.
Each of these cards carry a Radio frequency identification chip which responds to certain radio frequencies. When these "tags" come into contact with radio waves, they respond with a slightly altered signal.
The response can contain encoded personal identifying information, including the card holder’s name, address, Social Security Number, phone number, and pertinent account or employee information.
Upon capturing this data, one is then able to program other cards to respond in an identical fashion (cloning). – Wikipedia
In order to prevent RFID focused theft, Jekyll & Hide line our wallets, purses, and bags with specially engineered RFID Blocking Fabric. RFID fabric blocks radio waves from getting near your ID and/or credit cards and sending this information to a detector or reader. Look out for the RFID mention in each product description.