Early in this thread, there was discussion about visibility, both for blending in while nude, and for rescue purposes. Items of colors that don't occur naturally in a specific area, and signalling mirrors were mentioned, and are great ideas.
In any area, but especially in desert and canyon areas, a cell phone is a great tool for being located for rescue at night. No, I don't mean by trying to make a phone call from a signal-dead area. Leave the contraption turned off to save battery power until it can be useful. If you need help and are being searched for by aircraft at night, watch and listen for the aircraft to approach you. At that point, turn your cell phone on, lighting up the screen, while aiming the screen to the night sky. A flight crew wearing Night Vision Gear (NVG) won't even need a clear line-of-sight to you, the glow will look like a small town just appeared. They'll be able to zero in on your location rapidly.
