My story of this problem might be of help to some people...
I've been having the 'blinking' problem whereby the screen goes black for a split second, for no apparent reason and totally at random.
I reported this problem to Apple at a Genius Bar during a separate repair. Since then, they've had the machine in 3 times, each time not being able to replicate or notice the problem. To remedy it, they've fitted 2 replacement displays and even to replacement top-cases. None of the repairs have worked so far.
I thought I'd call AppleCare to ask if a replacement laptop was best. They passed me through to Customer Services who, as friendly as they were, took issue with my request. Despite telling them this appears to be a common problem, the whole 'investigation' took a very cynical tone as soon as I mentioned 'replacement'. She told me to get it checked out one last time at a Genius Bar. When I went this weekend we had a considerably longer chat, and the Genius consulted his 'Administrator', and they decided this was the last time they'd look at the issue. They couldn't prove it existed and so it was my word against theirs - without saying so, the Genius basically accused me of lying to get a replacement. My last ditch effort to get this fixed was to let them take the laptop for '7+ days' (ie. indefinitely) until they give up, but if they find nothing they're going to stop doing any diagnosis over this issue.
I'm VERY annoyed at Apple for their stance on this - making out I'm lying, having 4 repairs done (totally 6 separate Apple Store visits!) and a very condescending attitude throughout. Be warned. I'll update you all when I hear back from them.