alt Hacker NewsThe accuracy of this geolocalization depends very much on peering agreements.
I don't know about the UD bit this will not be very accurate within the EU.
As an example: In Hungary, there's pretty much only one peering hub (bix) and there's only one Cloudflare datacenter. You've already geolocated me better than this hack just by knowing my language or phone prefix.
It's not because you have a Hungarian number that you're not travelling somewhere else. I don't really understand the point.