this is their duty to check for our safety. always be polite with them, they will not open your luggage. I travels many times, never they open my luggage. one time I have something of stone (chattoo watta, dont know english:grin:) in a carton. the person on scanner tell me to again put that carton in rotated position. I put rotated position, then he tell me you have that thing, that was not showing correctly, so I tell you to again put in rotated position, otherwise we need to open this carton.
otherthan this never happened any thing, or never they tell me to open any luggage.