I wonder if there is something which accelerates / causes this issue, like climate, cleaning with a particular cleaning agent, or touching the screen. I've had my rMBP since it was released in 2012 and have not seen the issue yet, despite using it nearly all day every day since purchase.
From what I hear it could be heat related. Do you use it all day, let it get very warm and then just close the lid to put it in standby?
I am wondering if this is because of a hot unibody case coming very close to the screen when it is closed. So, someone who uses his MacBook very lightly so it doesn't get very hot and then powering it down completely and then waiting a bit before closing the lid might not have this issue as his MacBook is already rather cold when the lid gets closed.
i had rust patches under palms when i had old Al Powerbook G4 something to do with my blood acidity, no one else had them. Better figure out what causes this. I think there might be a limited number of wipe downs you can do with these and perhaps if there is something else present that might be accelerating damage, environmental and the like.