Also on using IPs to look up country & city, note that what you get might not be entirely accurate. If their ISP is based in a different city or province/state, the IPs may be owned by the head office, and used across several areas.
You also have rarer situations where they might be SSHed into another server, on the road, at work, at a friend's... It's a nice idea, but as the example code shows, it should only be used to set defaults.