New skill or few skills that would allow us to track other people, not only criminals.
Pilgrims tracking require f&w 50, h&g 40 and allow to see footprints on ground (not on map). Higher profs levels give you ability to see older footprints (in time all should slowly disappear).
Why we need such things? Simple I want to see who was near my camp when I was offline, even if he does not leave any scents.