In and of that particular instant and looking at nothing else, both are equally realistic and consistent and valid.
But there's a bigger picture to consider: first the easy one, whether the right-hand path being more travelled makes sense with what has been determined in the fiction leading up to this point; and second the harder one, whether that determination now is going to risk leading to things appearing later that should have (or could have) been known or telegraphed sooner.
On the first point, I would say that predetermining things actually creates more risk of inconsistency. Certainly a new element that is introduced can't contradict what hasn't been established, right? So this seems a pretty pointless concern.
On the second, I would say that this is a more valid concern, but that I think it's far less of a big deal than you seem to think. There's nothing that says new elements introduced in a more narrative game must come from absolutely nowhere. You can build to things just as you can in a traditional RPG.
In a pre-mapped situation the GM [and maybe everyone, depending whether a) the map is already known or b) someone in the party has flight capabilities and went up to scout] will in theory know what both paths lead to before the party get to the junction, and that knowledge will then inform the tracking results. Internal logic is maintained.
If they already know the areas beyond the branching paths, then there's no real need to focus on the amount of traffic at the fork. Certainly the traffic at the fork might be the trigger for such exploration....which can then be narrated accordingly in either method. The GM can read the boxed text or paraphrase from his notes, or the GM can call for dice rolls, and then construct what is found there based on the results.
I think that in this case, the predetermination may be helpful for some GMs. I myself find that kind of stuff very helpful, depending on what it is. But I also love determining things on the fly. Or a combination of the two things, which is I think what most narrative games really are; the GM has ideas about what may come up, often very informed by what would be challenging or meaningful to the characters, and then lets the dice roll to determine how those things come into play.
Because unless the entire idea of setting exploration is denied to the group, the players don't know what's out there that they haven't seen yet. If for example the GM already knows that the left path leads to an orcish village while the right path leads to a rarely-used dock on a lake then the GM could have in various ways telegraphed or breadcrumbed these things earlier had the opportunity arisen. But if the GM doesn't know these things then she can't telegraph anything; she can't describe elements of the scene that might very logically be there (e.g. that the traffic on the left path is probably all orc) because she has no way of knowing yet that they would exist.
I think this is likely one area where the misconception of narrative games comes up.....it's not all being determined on the fly by improv. Certainly the PCs are heading in a certain way for some reason. Very likely they have an idea of what challenges may lay ahead. The GM'll have an idea about all this regardless of the game type, and likely have discussed this with the players in one way or another.
I don't have to have in this case, if a dumb bozo like me can see how easily it'd fall apart.
Actually, you do. I mean, if you want to have an informed opinion. You can certainly put forth any assumptions you want about anything. But without actual knowledge to back them up, that's all they are.....assumptions. Even the ones that may turn out to be correct, they are mere assumptions.
The only way it wouldn't happen is if the players were extremely forgiving of inconsistency (which IMO is close to unforgivable if it happens all the time) or simply didn't care enough.
I can imagine that it may seem this way without having firsthand experience. But you are incorrect. There's nothing about such games that makes them more prone to inconsistency than any other game.
