How reliable are GeoIP services for mobile roaming?

Question

Currently, I'm using Quova but I'm struggling to find/understand the accuracy of GeoIP (to a country resolution) when a user is on a mobile network (not WiFi) and roaming outside of their home country.

1. If the IP address of a device is allocated from the home network, then obviously GeoIP isn't going to be accurate (in fact, it will be plain old wrong).
2. If the IP address is allocated from the current country network, then I'm sure it will work fine.

Does anyone have any information / figures on home mobile networks allocate IP addresses (and from where)? Is it generally (1.) or (2.)?

Answer 1

In S. Triukose et al., "Geolocating IP Addresses in Cellular Data Networks", unpublished(?) http://people.cse.iitd.ernet.in/~aseth/ipaddresses_geolocating_cellular.pdf, section 4.3 states:

We also observed an outlier at 17,000km (not shown on the plot) 
which correspond to an Australian user roaming in the Netherlands.

If I understand your question correctly, it seems like in this case, it would be number 1.