You don't need the backdoored lock. The TSA will helpfully use bolt cutters on any locks they don't have a working key for. Source: Me and my suitcase a couple

You don't need the backdoored lock. The TSA will helpfully use bolt cutters on any locks they don't have a working key for. Source: Me and my suitcase a couple of years ago. (Which had a TSA approved lock on it!!)