I see it regurlarly that german people are carrying IP's from other countries depending on their service provider in my shop. AOL for instance assigns US registered IP's to whoever they feel fit.

In my experiments with per-country IP classification, the main issue, apart from ARIN's reluctance to give their list, was AOL. They have enormous blocks of addresses registered in the US. I don't know how to tell apart European and American AOL users.

(This goes back to some years ago, so my information may not be current.)