Indeed it isnt exactly matter of if they "could" ... more like if they "should". laugh

Enlargening danger zones would potentialy make sense, from story perspective ...
But from gameplay perspective they would once again be easily negated by player who simply first run all side quests, while zones are all friendly and cozy ... and then start working through main story, when "dangerousness" of those locations no longer matters, since you dont stay there for long. laugh

Backtracking have simmilar problem (btw you cant fast travel out of Hag's lair as far as i know) ...
From perspective of player who likes system restrictions for resting, and random encounters (meaning GM4HIM for example) your suggestion probably sounds good, bcs he have exactly what he want.
From perspective of player who dislikes those things (i would once again use Icelyn as example) it would be pure nightmare. :-/

Just try to imagine the situation:
You just ended the fight, it doesnt really matter if you just poorly managed your resources, or you made few stupid decisions, or you are simply unexperienced player ... the outcome is that your group is in bad shape, you are out of resources (both magical and consumables) and you desperately need to rest.

Have it? Good.

Now ... it splits up to two scenarios:

- Curent situation:
You rest ... you heal, restore your magical resources, you are totally able to continue your adventure. No complications at all.
You as a player are happy in that situation.

- Suggested situation:
You have choice ... either you continue and meet another encounter that will most likely kill you, and your game ends ... or you return, and have fair chance to meet "random encounter" that will most likely kill you, and you game ends ... you cant rest, you cant fast travel ... all you can do is either reload right now, or try one of previously mentioned options and pray to gods of dices to give you good numbers, so you dont meet anything hostile.
You as a player are happy in such situation? I doubt that. Personaly i would certainly not.

In the words of the senior NCO instructor at cadet battalion:
“If you ain’t cheating you ain’t trying. And if you got caught you didn’t try hard enough!”