"...needing to direct a helicopter to a safe landing zone..."

You might want to rethink that one. I was once on a day hike (eight miles round trip) with three friends. Before the day was out we needed a helicopter to lift one of them out. Luckily, in this case, we were at a very prominent location (the top of Half Dome in Yosemite), and had a ranger on scene with a radio, but change a few things and we might have needed to direct that bird in ourselves. On other occasions I have directed choppers in with a mirror, and even though I had radio contact with them, the mirror made it easier for them to locate me. A mirror is small and lightweight, why not stick one in your kit???