Funny how opinion is divided here. I am NOT a professional (far from it), but I would note that:
A LARGE percentage of super high end guitars are purchased sight unseen because they are custom ordered - via telephone and/or internet (even though this is conceptually different than what's been discussed here). Most of the boutique luthiers sell the great majority of their instruments to pros in this fashion. From conversations with more than one of the jazz-box crowd, I've gathered that 3/4 or more of their output commonly goes to pro players that they have never met.
Also, note that Benedetto runs Bob's Boutique on their website- finished inventory at 20% off list. They've told me that a fair bit of this stuff goes to pro players, too, and that IS what we're discussing here. I guess that there is divided opinion in the pro community as to the wisdom of buying on-line.
BTW, these marvelous instruments often turn up for re-sale on sites as pedestrian as e-bay. This economy has hit a lot of professional musicians hard and asset sales have become a life line for many. Just search for Monteleone, Benedetto, Buscarino, D'Aquisto, D'Angelico, etc. and you will find some of the greatest jazz instruments in the world listed for sale - at prices that run well into 5 figures, as expected.
My only advice - if you do buy on e-bay, know exactly what you want and know who you're buying from. Also, make sure that you can return the item - generally SOP.
Marty
