Having people on watch doesn't mean your rest will go undisturbed. In reality, resting should take a few hours, not a few seconds while the meter runs down on your screen. In lairs that are occupied by active inhabitants, like the goblin caves, it seems unreasonable to expect that the owners would just let a group of hostile invaders camp out freely in their own home. Part of the challenge in this mod is learning to manage your time and your rests, as opposed to just recharging your spells and abilities whenever possible.