Can anyone here describe the merits and/or drawbacks of "Zero position" frets, or why you would want or need them, or for that matter, what they're supposed to do? I recently noticed an MTD American that had a fret in the zero position just below the nut, which I've never noticed on other basses. I'm guessing that sliding up from 0 might be quiter, but other than that, I'm not so sure. Anyone care to comment? Thanks!