From Notes on Camp to notes on camping ... I guess it makes sense. Inspired by this post of Telecanter's I boiled down a simple rule for the wilderness.
A tense camping situation is one in which you are foregoing the normal comforts of rest time - song, chatter, fire - in order to be inconspicuous. In this kind of situation, cowering silently in the dark, you only recover 1 hp / night no matter what your level. Bear in mind that I see hit points as intangible shielding against serious physical injury.
In a normal camping situation you incur a greater risk of encounters but sleeping recovers you 1 hp per level per night. In a sense the higher level characters get more benefit from whistling past the graveyard and living large.
In some of my previous games I tried and failed to grant this rate if you were not keeping watch -- it just didn't make sense in the wilderness and I could never get players to see that not keeping watch is a sign that you are feeling secure. So now, I'd say that if you have a normal camp you can keep watch and that might even help people feel more secure.
Now, for parties that insist on keeping watch when they are guests in an inn or someone's house... In civilization the expectations are different, and keeping watch (like CCTV cameras) makes you feel less safe, not more safe. So reverse the roles -- paranoid behavior at an inn will bust you down to the lower recovery rate.
Sleeping in armor definitely means you are not having a comfortable camp, no matter where you are.