The idea that any and every screen will develop burn in or image retention is simply not true. This is outright lying, or sheer incompetence.
I have six displays at home, a MBA plus Samsung screen, and a rMBP with three other displays (two Dells, one Apple Cinema Display).
I have owned about 30-35 computers since the late 80s, and many more external monitors, at home or at the workplace. This is a ridiculous claim.
For instance, my Apple Cinema Display 27" (version prior to Thunderbolt, so at least 2 years old) is on many hours a day, and I disable my screen saver when I am sticking around. I can display various windowed apps on it for minutes to an hour at a time. Never had one single IR issue with it.
Even the ugly arse Dell displays exhibit no IR at all. And they certainly are inferior in quality to my ACD and rMBP displays!
Apple is producing hardware at an ever increasing rate, and unfortunately I see this as translating into poor quality control.
None of my pre-Intel Apple hardware had display issues, in fact, all of my friends/colleagues' iBooks G3, G4 etc. had *identical* display outputs, in terms of coloration, contrast, etc.
Ever since Apple took over a sizeable share of the market with Intel laptops, phones, and tablets, there are now more and more discrepancies in terms of quality and uniformity to their own 'standards'.
No two iPhone displays I see around me look the same, and it's certainly not because of calibration... My 3rd gen iPad has a great display (I changed it once 2 months ago because of stuck pixels, mind you), but one of my iPhone 4 and my current iPhone 4S are yellowish in a sickly way...
My rMBP has this stupidly easy IR which occurs pretty much 2 to 3 minutes into using clear/white windowed apps then switching to darker/gray backgrounds.
It's embarrasing and ridiculous. It looks nothing like a pro screen on a pro computer. The question is, if the ghosting is so obvious and quick to reproduce, how come it got through with quality control in the first place?
Sounds like someone at LG Corp should get his pink slip.