TSA locks - even the combination locks - can be opened with a master key that TSA agents have available. With the plethora of zipped luggage nowadays, using something to secure the zippers can make you feel more confident that your luggage will remain closed throughout the journey. Some people report using nylon zip ties, but if TSA decides to open your luggage after you've gone on the the boarding gate, there's no way for you to refasten it. Use of the TSA locks should solve that problem. (No, I do not sell TSA locks.)