I just bought a handful of them too. One of the reasons I'm real intersted in these is that it seems a Sharpie will do a great job of writting on bright plastic survey ribbon, which I've included in my kit. I'm only mildly concerned about them freezing up in cold weather, since I'd suspect a few minutes in a warm pocket would get them working again.

I really like Cody Lundin's suggetion to use the ribbons to leave notes for searchers, but I know pencils wouldn't write on them well and suspect many pens won't either.