On resting in Dungeons: In what adventurers generally call Dungeons, it's not so bad. That is, if there's no group or force that would mount an organized response to them, yeah, I can see that happening. Setting watches, barring doors, and so forth are a given, mind you, but random unintelligent and/or wandering monsters in a dungeon (or other groups of glorified grave robbers and looters adventurers) are unlikely to make a concentrated effort to kill them while they rest or overly prepare to kill you once you break up camp. Making a metaphor, it's like setting camp somewhere with dangerous animals: If they stumble upon you or vice versa, they'd probably try to eat your face off, but otherwise they aren't likely to change their behavior and routine because of you and your camp either. Sure, it's a bit of a stretch that there's no chance for random encounters or for the monsters next room not to walk out to you, but tolerable enough, let's call that an abstraction of finding a room that they could barricade themselves in or something.
Now, on the other hand, camping somewhere where there's intelligent beings living there as a group but hostile to you, like an "active" castle that you are infiltrating or attacking? That's bull****. If you didn't killed any of the guards or actual pets, maybe, or if you killed someone who barely interacted with the rest of the castle (Say, the monsters, the undead and that Animancer beneath Raedric's Keep), I could see it happening for maybe a while before people start finding it weird and sending someone to see why no heard from her in so long. But if you killed a bunch of guards in the middle of the ramparts and/or just in front the throne room, and then went to rest for 8 hours and there is no reaction to it? That's entirely bull****. You might get away with "vanishing" a small handful of guards if you are careful in getting rid of all evidence, with people assuming they went AWOL or suffered some accident, specially if it's a dangerous location ("He probably went take a piss and got eaten by a Forest Troll"). But with enough guards vanishing and leaving no trace? Yeah, no. Even if you are the master of Stealth, at least it'd be needed to see more guards being hired and patrols increased and relocated, while paranoia goes the hell up about it.
Of course, that dynamic would be rather hard to program, but even a bit of a restriction of resting in "civilized but hostile places" along with a respawn of enemies if you go rest somewhere else would be rather nice.