RFID tags have very small storage. It's easy to assume they can't be used to attack other systems. It's not true. Data from the tags can be modified to cause buffer overflows, SQL injections and other attacks. The reason? Software that receives the data do not always parse it correctly.
It's nothing new. It's nothing new to read opinions like the one below (written until first big crash of the new system):
While we have some hesitation in giving the ''bad guys'' precise information on how to infect RFID tags, it has been our experience that when talking to people in charge of RFID systems, they often dismiss security concerns as academic, unrealistic, and unworthy of spending any money on countering, as these threats are merely ''theoretical.''