"unlined folk" - does that mean they ran out of coke?
What is interesting is that I have far less of an issue swapping between the RA (35" scale) and Zon (34" scale) unlined than I do when I pick up a lined fretless (no matter what scale).
Playing above the 12th fret is for wankers anyway. Well, so are 5/6 strings, and for that matter anything other than a P-bass with flats. And even then anyone who uses the G-string is suspect and may have to be taken into custody.
Oddly enough, this guy wasn't against 5-6 string basses, just adamant that you can't play the 2nd octave without lines and he has published instruction books, although on guitar. I guess he got irate when he didn't win the argument.

