Hike for Fun, under my and more... comment I always include a space tarp, and in one of my many kits, is a fist sized space blanket that I have always been skeptical of, but never unpaked because it is currently very small and my repacking skills lack.
The estimated reason for being out all night certainly vary but I believe they rank as: 1. went down something under different snow conditions later in day and the snow softened up to the point of having to wait for it to firm up again, to climb that hill, 2. out of gas due to either incredible stupidity, = but probably a lost and looking for way out too long under adverse visibility(now I have a GPS but batteries die), 3. multiple breakdowns, or multiple very stucks, 4. Hurt and unable to get to trailhead and not wanting to split up till? morning. 5.6.7.... any multitude of issues, but stupidity probably is the common denominator. But number one seems to be rather common among the spent the night snowmobile crowd. But Hurt and unable to get wood is a new thought, and I'll have to consider it, but the buddy system is a must for me, so I'm assuming we both aren't hurt, but you never know! Oh, yea, I almost forgot AVALANCHE, that could hurt multiple riders? Fuel and a stove might be a good idea?