Yes, I wasn't implying that your game rolls were illusionism, or that all random rolls are. I was talking about the scenario in the OP (and assuming that the same encounter table was used for both roads).I rolled on the tables as the rules dictate. If the players had not entered Town Phase, no Town Event roll would have been made. Had they not entered Camp Phase, not Camp Event roll would have been made. Had they not beaten off the bandits who ambushed them, no Loot roll would have been made.
The rolls are triggered by particular sorts of events, which in turn flow from particular sorts of player action declarations.
In classic dungeoncrawling, the GM typically doesn't advertise their rolls on wandering monster tables, but these aren't illusionistic either. The players know that X turns of activity will produce a wandering monster roll, and by choosing to spend time, or not, on various things can pursue a balance between the benefits of exploration and the risk of wanderers.
If the GM makes the same rolls at the same rate, regardless of whether the players have their PCs choose the "dangerous" or the "safer" road, that does suggest illusionism, and also more generally a very casual approach to the relationship between colour/flavour and actual methods of framing situations.
But if danger is reflected by more frequent encounter checks, then the first encounter on the "dangerous" road will occur sooner, in terms of ingame time.
As I discussed in a series of posts on the first page of the thread, the players may or may not have agency in this situation - but if illusionism is involved, it wouldn't be in the fact that the same encounter table is being used, assuming that the "danger" does, indeed, produce more frequent checks.
If you think that the same encounter table for two roads is in bad faith, let's use the scenario of a small dungeon with only one faction, where you are faced with the choice to go left or right, and based on the information (maybe a partial map left by a dead adventurer) you can determine that one path is short but dangerous and the other is longer but safer. IMO, a single encounter table for a small, singe-faction dungeon is reasonable.
I don't think that time is really a factor. If the DM decides that regardless of which road the PCs take the next encounter is a red dragon, it's still illusionism even if the encounter takes place on Day 1 for the fast road and Day 2 for the slow road. All that means is that their choice of route had (some) agency. The encounter itself is illusionism, despite the choice of route having agency. IMO, this also applies if instead of simply deciding on the red dragon, the DM rolls on the same table at the respective time interval for either road. Presumably, the rolls would have been the same for either path, unless we want to get philosophical and question whether the players' choice alters the quantum state of our universe, thereby resulting in different outcomes for the rolls in the two hypothetical timelines. But I'd rather not go there.