A sign in register is used on public land for a few reasons. If you get lost or injured, your entry in the register gives the searchers a place to start looking. It also helps the overworked land managers keep track of who is using or abusing a public resource. Some mountain peaks in Utah and probably elsewhere also have a visitors log, (the last one I signed was on Mary's Nipple near Gunnison) and its cool to see who else made the climb and what their impressions were.
