I see. How do you know that?
I ask them. We have allowed Hispanics into our formerly all Germanic heritage family for over thirty years now. It's only in the last two years we've opened up to the Irish and Israeli's. So it's simple. You ask them or engage in conversation.
Of course one needs to be around Hispanic surnamed people to do that. But, then on the West side of San Antonio, and almost everywhere else in San Antonio one can find someone with a Hispanic surname if they try hard enough.
Remember my qualifier was, the ones I meet.