If your luggage has a built in lock like on hard sided luggage, the TSA
will break the lock if they have to open it up and inspect inside and leave it unlocked. If you have a soft side with a removable lock the TSA
recommends that you use a nylon tie wrap. I buy these by the bundle in Home Depot and use them all the time, the cost is just pennies each.
If the TSA
opens your luggage, all they have to do is cut the tie wrap and then they will place another tie wrap through the holes to lock the luggage.
Some airlines are also supplies these tie wraps at luggage Check in.
To cut the tie wrap, carry a nail clippers, they are allowed to be carried on board with you or put it in an unlocked pocket on your luggage, Also carry additional tie wraps for the return trip. One recommendation, do not pull the tie wrap tight, leave about a 1/2" loop so you can easily cut into the edge of the loop of the tie wrap with the nail clippers.
I have traveled numerous times using these tie wraps and have had no problem
with my luggage being left unlocked by the TSA
or cutting the tie wrap off when I have to open my luggage.
Also at some airports you can watch your luggage go through TSA
inspection and if it passes you can go and place your regular lock on your soft side or lock your hard side. I have done this at JFK
. But at other airports the luggage inspection is out of sight.