They did go through our carry-on bag by hands on the way back - that's because I put my camera in it. Complex patterns on screen == hand search. If I had that camera out, it would have been even easier.
Just because it's possible to circumvent the system, does not mean we should discard it. It may not stop or deter 10 out of 10 terrorists, but 9 out of 10 is OK and worth it.