They now make TSA locks with a SearchAlert feature that shows if your luggage has been searched by TSA. It adds a little measure of security, rather than leaving everything completely unlocked and being too easy to mess with.
Luggage checked at an Airport is sent through an electronic screening. If a TSA agent determines the luggage needs to be hand searched, the SearchAlert lock will be opened by the TSA agent. When the TSA secured access device is used, the SearchAlert window changes color from Green to Red. The SearchAlert window should also change color if the luggage lock is tampered. If a TSA Agent hand searches a piece of luggage, the agent should leave a TSA Notification of Baggage Inspection in the bag. If the SearchAlert lock Security Window shows red, and no official Notification of Baggage Inspection is found, the traveler should take the luggage to the airlines baggage services office to determine if items are missing items have been added to the luggage.
