Just for the sake of debate, why is it so relevant since no customer listens to the products unsighted?
It's a reasonable question - why not use sighted evaluation as the standard:
Sighted evaluation is inherently biased by other effects - the appearance of the gear, the time of day, frame of mind, expectations, etc., which I will summarize as "mood". So think of your listening impression as the sum of the pure sound (unsighted) plus mood. While some of the effects of sighted evaluation are stable, such as appearance of the gear, the mood inputs, at least, are not stable. As a result, your impressions of the gear will not be stable. One thing will work for you over time - you will acclimate to the sound of the gear (described inaptly by subjectivists as "break in"), but in other respects, your experience will probably vacillate around the more stable unsighted impression as mood inputs change.
I believe this reversion to sound is why so many audiophiles get hung up in the upgrade frenzy. That cable that perfected their system a few months ago is no longer doing it for them. And that realization will actually have positive feedback into mood and make things worse. Off to find the perfect new tweak. Of course, you can't admit the last decision was bad, so it must now be some other part of your system...a cable, perhaps.
In sum, sighted impressions are unstable and the customer's satisfaction may revert to unsighted levels over time. For these reasons, if you are aiming for *long term* satisfaction, unsighted listening is how a manufacturer should determine preferences.
Another important consideration, in my view, is ethics. Vendors should not make
claims about sound without experiments that control for
effects that aren't sound. As has been said around here many times, Rolex is not telling people their watches tell better time than a Timex quartz. They might, if time weren't so easily checked.