How can you "Hack FedEx Kinko's ExpressPay system SmartCard?"

Question:
How can you be sure to ensure you'e not exposed like you don't think you are/?

Source:
YouTube - Hack FedEx Kinko's ExpressPay system SmartCard: "The ExpressPay stored-value card system used by FedEx Kinko's is
vulnerable to attack. An attacker who gains the ability to alter the
data stored on the card can use FedEx Kinko's services fraudulently
and anonymously, and can even obtain cash from the store.
Added on March 03, 2006, 01:19 AM by xerohour"