Re: Works for Waze too
Waze asks other users for confirmation and takes the numbers into account when re-routing. You'd either need to do this same thing with many phones or report an incident (crash, roadworks etc) to affect it. In the former case, one or two cars passing through unimpeded would undo your work, and in the latter case a few users hitting "not there" would undo it.
On top of that, if you are frequently reporting things that other users mark as incorrect, a behind-the-scenes credibility score drops and the weighting of your input is reduced.