I understand and probably agree with your reasoning, but just to throw a different perspective in the mix: DEN-NRT r/t is 28 to 30 hours of BIS. To do that much BIS on short domestic hops would take perhaps 10 to 14 segments a month, which I think you would classify as FF. So, perhaps not frequent in terms of segments or times passing through TSA checkpoints, but frequent in terms of total hours on board an airplane.