Don't they x-ray ALL baggage, not just carry-on? I know after September 11th they started having an xray machine for checked baggage and had you put it through, wait for it to be screened, and then a security gard putting it away and saying your free to go (onto YOUR security checkpoint for you and your carry-on). I always figured they used these all the time but just behind where your undercarraige rolls away into. It sounds like I'm wrong though if what iStaaHi says is correct. But if so, wtf mate? Why don't terrorists just put bombs in undercarraiges and then not get on the plane?