My question was based on the fact that even with automatic exposure the scene may be "darker" than a photo you take at another time and location...

In extreme terms, if you think of how a photo comes out if you point it towards the sun and then take the photo immediately behind you, the camera may expose both scenes "correctly" but they will be completely different in terms of lighting.  Therefore they should need a different setting when processing, even with HDR tonemapping and 3 exposures on AEB i would have thought...

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography