I don't know how they don't notice thousands of users driving through these "cornfields" at 60mph every day, though. You'd have thought that'd raise some alert?
Advertising slightly heavier traffic isn't the worst thing in the world. Telling hundreds of motorists "There's a navigable road here" when there isn't, is a bigger problem, for both Apple's PR team, and the motorists in question
Verifying indepenantly is probably the reasonable response
Waze was pretty public about how they used it, with automatic flags and route updates with no/little human intervention. I assume everyone else is doing the same, since it's so obvious. I'm sure they know, but if it was a cornfield a couple years before, there's a good chance it's lower on the priority list, in a "how many people will this impact" sense.
Yet thousands of cars doing 60 mph through a cornfield and over a river doesn’t trigger a “maybe a freeway was built here?”