The only issue with this is that it uses "full" caches in order to get that data. For Premium users that isn't too bad since you can load 6,000 full caches per day, but regular users get 3 per day. Also, I wouldn't want to implement this without it being off by default since premium users could pretty quickly use up their caches if they were really exploring around the map.
We do have this on our list, but these are the major reasons why it hasn't been added yet.
