I don’t like random monsters. On the other hand, the idea of having players sweat for their extended rest could be worth exploring once or twice in a campaign. This is especially true if your group chronically blows their wad of dailies in the first encounter and then just assume they can take an extended rest wherever they please. So, what if you said ‘Yes’ to resting in a dangerous area (like in the middle of a freaking dungeon) but did it with a twist?