Ask HN: Overcoming Authentication by Country?

I'm a UK/Australian citizen currently living in Berlin, with bank accounts scattered all over the world after travelling for a few years.

I always have problems signing up for things, because services always assume that my nationality is the same as my country of residence is the same as my bank account nation is the same as my mobile number prefix is the same as my postal address is the same as my language preference is the same as my IP geolocation.

1. Why do site developers always assume things about my nationality/country/language? Especially now that VPN's are common and we can "be" in any country online.

2. Anyone got any ideas on how to create a consistent online persona while travelling?