Why would it be different if the player had rolled a specific result, and as a result you knew there would be terrain or a situation that was logical?
It does not matter who made the roll, it's the purpose of the roll and what the roll represents. A sleight of hand to open a lock is simulating the act of picking a lock, nothing more. A random encounter roll is used to resolve uncertainty, a monster could be encountered in this area over this period of time but it is uncertain whether or not they will so we roll for it.
But that has quite literally been a core point for the thread for hundreds and hundreds of pages at this point. That it IS simulating reality, that it IS trying to do that thing.
Whether it works fine for what you want it to do is not the same as whether it is well-constructed for the purpose of simulation. As pemerton has now explicitly said just above.
D&D is simulating a world independent of but influenced by the characters.