Yeah I get that I just don't get why screening it before it gets on the plane isn't more reliable. A jihadi is quite happy to die onboard so I am concerned to say the least that the bag isn't screened to a standard where it no longer causes concern. What's the big deal stealing all the water from us at security if the hold luggage isn't confidently screened? The US are security paranoid and they allow unaccompanied bags to travel. Lockerbie was 20 years ago, one assumes technology has moved on.