"Guiri" is a term used in Spain that means "foreigner." It usually refers to Anglo-saxon Europeans and their descendants. It is similar to the Mexican "gringo."
Everyone has biases. We make assumptions about people based on their looks and even on the clothes they wear. These are just a few of my personal experiences with people making guesses, largely based on what I was wearing at the time and the fact that I am a blond, as to where I am from.