Great! Lat/lng would of course be best implemented if kind of accurate. Ipinfo.io seems to do this quite well. I would happily use this to detect if somebody tries to spoof the info provided from window.gelocation.get/watch, whic is pretty sweet to utilize for anything that relates to maps. :)
Slightly related, what can someone do with the lat/long in that data set? (since there's only a canonical lat/long for each country)