Exactly! I seldom use the precise route prescribed by the navigation system, since it likes to take me through congested areas that could be avoided entirely.
It is very likely Alice would know multiple better routes.
By the way, i'm very happy with GPS. Since my wife can't stand anybody else driving a car, it's always her piloting the car when we're abroad together. In former years, she always asked me which way to go. Not to follow my recomondations, but to argue them and drive it her way. But she wasn't able to recognize signposts whatever. Every time we got lost (and we got lost), she turned into ALICE.
Since GPS is on board, we had no arguments about the right route to take anymore. She just follows the commands given by a female voice, with no need to care for signposts.
Alice might have expressed her disagreement with the phone software more mildly ... nah, scrub that, not Alice. Based on my experience, I would not rule out the possibility that Alice is correct that the recommended route is non optimal (e.g. may not actually exist).