Actually, yes it is. And I'm being serious. Obviously you can't grow something but there is a security hole that, with a little planning and time, would grant you very easy access to just about anything that is carry-on size. The average person wouldn't use it; however, the type of person that the TSA claims it is trying to stop would certainly use it. And I'm not telling them something that they don't already know.

This is not to say that I support gate screening or TSA in general. I'm just pointing out that yes, you can go through security without a prohibited item and still board a plane with a prohibited item. Not including liquids purchased airside. Although that should give you a clue what i'm talking about.