My belt used to set off the metal detectors, but after a one time, a TSA officer taught me to keep it on without setting off the metal detectors. I think it was my early morning daze, rushing to catch a 6am flight, that after I placed everything through the xray machine and just before I pass the metal detector, I realized my belt was still on, so I told the TSA officer. He just asked me if I want it off or on, and it was a hassle to take it off and on again. So I told him I want it on. He just asked me to use my hands to cover the buckle, and that same belt has never set off any metal detector since.