The lines cannot be "fixed". The Apple Store employees all but promise it when they say the cannot guarantee that sending it back for repairs will fix it. And as has been posted elsewhere, Apple officially says these lines are within design spec - the textured/grainy line pattern is "expected".
Further - and importantly - the degree to which the lines are visible in fact varies alot. If I try very hard in a room with controlled lighting, I can see lines on one year old Rev A machines which are barely/faintly visible, but are there - you have to know to look for them. The new one I had last week was quite pronounced and obviously visible within a second.
My conclusion is just that there are some machines that come out with the lines less visible (but not "gone"). I truly wonder whether Apple's engineers have a lineup of 10 airs with varying visibility of these lines (call it 1 to 10 on the line scale). I do not think they do, or they would have a different response than "this is part of the design".
In the end, what completely shocks me is that Apple would "design" it this way. And given the company's usual anal nature (and experience with G3 cube mold lines) that they would allow such *variation* in the product, which leads to all of these customer and quality issues. And given the response to date, its clear they do not have the ability or intention to fix it during this model run.
I am disappointed not by the existence of the lines but instead by the variation. It is completely out of character for them, and not something I am comfortable paying $2000 for.
