From what I understood, because of the "homeland security" tie between Customs, the Coast Guard, and TSA, TSA can report suspicious substances or paraphernalia to Customs or law enforcement. I could be wrong about this though. I just vaguely remember reading this is another thread.

Also, regarding transporting cash, I thought there was a limit of $5000 or $6000 that one could bring through an airport. I know that if someone is searched by law enforcement on the road or anywhere else and is found with greater than $6K, the officers are obligated to confiscate it without returning it -- even if the citizen is never charged with anything. This provision was put in place as one of the maneuvers to "fight the war on drugs."

Similarly, any bank transaction greater than (I think) $10,000 is documented and forwarded somewhere, also to help fight the drug trade. This is the "Know Your Customer" initiative that was put in place a few years ago.

I suspect that these initiatives are in place as much to prevent USD from being laundered and moved offshore or stuffed under mattresses than anything. The more cashless we become, the easier it is to regulate the traffic of the currency -- and to keep track of it for taxation enforcement.

If TSA's scope does not include this sort of thing, I have no doubt that it will broaden in a matter of time.