That's the same reason why some US-based stuff I receive insists on using my mother's surname as my "surname" instead of either the first one ro both of them. I actually like bearing both of them, otherwise I would have the same name as my father!
There are some fun cases, when someone's first or second surname are a composite one, and the person has three names:
Given Name: Maria Alicia Norma
Surname 1: Lopez Velarde
Surname 2: del Palomar
Full Name: Maria Alicia Norma Lopez Velarde del Palomar
Guess why I have to use varchar(50) for those fields when setting up databases...
PS: Latin American countries will do hideos things with their male population, putting them FEMALE names like "Maria" or "Guadalupe". Ow!