I don't really understand how that squares with the statements folks have made regarding non-planning from the GM, and I think this is at least adjacent to pemerton's questions. Specifically, this implies that there is, in fact, a planned sequence of events that will happen, and the PCs have found a shortcut which skips some of that planned sequence.
Given the pretty strong feeling in this thread about even the slightest suggestion that something has been pre-planned, rather than various other perspectives, I am...more than a little confused by the way this is presented. That is, the presentation seems--I stress, SEEMS--to be far more like what I hear in non-sandbox contexts, where the GM has set out what will happen, but there is some room for PCs to weave around/over/through those things.
Have I missed something? The impression I've gotten thus far is that anything even like pre-planning a sequence of encounters would be verboten. Which, again based on the impression I've gotten, would mean that it isn't possible for there to be a "bypassed encounter". There are simply entities in the world. The party might interact with them, or not interact with them.
It’s similar to a plan of battle, and in play it should be treated as such.
When drafting a plan of battle, a commander plans for what could happen and what they would like to see happen, but they understand that’s not what will happen. So the plan includes contingencies to prepare for the unexpected.
Even after the situation spirals into something unanticipated, the original plan still has value, logistics, availability of forces, lines of retreat or reinforcement. These elements help inform decisions as the battle unfolds.
In my living world sandbox campaign, my plans focus on what could happen. Unlike a military commander, I have no stake in the outcome beyond making sure the result is fun and engaging for the players. But I still need contingencies, because player choices will cause events to evolve in unpredictable directions.
The original plans remain useful because they contain detailed information: who the NPCs are, what their motivations are, what the locations are like. I’m under no illusion that what I imagine ahead of time is what will actually occur at the table, but because I have those plans, I’m more prepared to adapt on the fly. I don’t need to pause the session to figure out how the world responds when the players disrupt or bypass something I’ve set up.
Hope that helps clarify how I approach this. And now that you asked this, I think this also clarifies why the amount of prep I do doesn't lead to predetermined outcomes.
P.S. Still working on the reply to your other post. It's just the question you ask is one I've been asked many times in the past, and thus already had an answer for.