This is a response to one of my classmate's posts on their blog:

I disagree with you that the TSA made the wrong decision to start allowing pocket knives on planes.  At a Penn and Teller show that my family went to, they demonstrated a plastic knife that could kill somebody, yet it got past the metal detector.  What is stopping somebody that wants to take control of a plane from getting one of those knives?  If they really wanted to take control of it, why couldn’t they take it without the knife?  Having a pocket knife is not going to increase the chances of taking control of a plane.  Given the cockpit security, if someone is trained to take a plane, they will figure out a way to get past the system.  I highly doubt that there will be an increase of attempts at hijacking a plane once this regulation goes into effect, nor will it increase the chances of attack.