It is not possible, that a single trader like Jerome Kerviel burns 5bn Euro

It is absolutely impossible, that somebody in a position like Jerome Kerviel can hold trading positions for 50 bn Euros and burn 10% of that amount. It is impossible, because

• banks nowadays would never rely on simple password protection for their trading systems.
• they all have state-of-the-art identity management in place and manage business roles in a way that one single trader could not crash the whole bank
• such big deals would always be routed through acknowledgement processes where duties are segregated
• Strong Authentication techniques and strict authorization would let all employees of a bank feel, that it is impossible to operate with multiple identities falsifying acqunowledgement processes
• risk dashboards would turn red and start screaming long before such a damage occurs