So, I think you should be able to tell the difference, the issue I think we have is that we have auto spawning critters, and they walk from place a to place b and then unspawn. I don't want people following random tracks to nowhere as that is frustrating. Might need to refactor this system so it is more usable-- maybe if the NPC despawns it removes their tracks or something, that way if you find something you know it is legit and worth following.
Maybe go the Diablo 3 route where every creature has a spawning 'pit' which as eggs or whatever so the goal is to identify where the critter spawned from not just find the critter.