Yes I remember watching a video on the Smith torch & they specifically said did not require flashback arrest. One would think in a lawsuit itchy country they would err on the safe side & recommend it be there. I really don't know if its the absence of oxygen line that makes it different (air is sucked in at the base of the torch handle mixed with acetylene downstream at the tip). So more like a butane torch principle? I'd be inclined to install FBA anyways, but good point.