Bottom line is it doesn't matter to the vast majority of us, because we cannot see the lines during "normal" use of our MacBook Air.
Yes, the lines may be there on some, possibly many, but NOT all rev B MBAs.
People that do find the lines are looking for them. The vast majority of the "line consortium" state they have to use weird viewing angles, specific backgrounds, and view from a certain distance, NONE of which is during "NORMAL USE" of the MBA. I have seen the lines, so I know what they look like, and I know how I had to see them - it was absolutely abnormal.
My question has changed since seeing the lines... does it matter? Does it matter if the lines are very faint and can only be seen from that distance, that viewing angle, and with that background?
I am not saying that Apple doesn't owe us each an absolutely perfect MacBook Air, as the Lord knows we are paying a small fortune for them. What I am saying is does it matter if there are lines, if we cannot see them during normal use. Should we expect that the display looks perfect from an abnormal view. If there are lines that are not seen at "normal" viewing angles, then who really cares; that is not the intended use of the MacBook Air.