Canon has completed its promised investigation into the light leak issue reportedly plaguing the new 5D Mark III. Some users have complained that keeping the top LCD panel's backlight on can affect the automatic exposure in low light situations, but the company has found that while the displayed exposure value may indeed be affected, the actual captured image itself will not. In short, your camera should still be exposing pictures correctly, but you might need to be confident of your settings — the screen may not be giving you trustworthy information.
We're not convinced that this will prove satisfactory to Canon's customers, however, and if you're convinced that your hardware is faulty the company is offering to perform inspections free of charge from mid-May onwards. It doesn't sound like Canon has any plans to make a recall of the camera, but it does note that only "products whose sixth digit in the serial number is 1 or 2 are affected" — it's unclear if this refers to specific batches or all units produced until now. It seems unlikely that a software solution will be forthcoming, either, as Canon also just issued firmware version 1.1.2 for the 5D Mark III with fixes for various unrelated bugs.