I would think that normal GPS maps intended as a navigation aid for humans don't need ultra-high precision. Even an offset of a few meters wouldn't be enough to

I would think that normal GPS maps intended as a navigation aid for humans don't need ultra-high precision. Even an offset of a few meters wouldn't be enough to confuse it about which road you're on and the direction you're headed. What's the worst that could happen? It tells you to turn right in 100 ft when it's really 105 feet? A human driver wouldn't even notice.