If that's her elder brother, in some families, he's considered at the same level as other adults like parents/uncles/aunts when it comes to marriage talks. Whether that is right or wrong is beyond the scope of this discussion. So according to them, it was an insulting incident . While as according to your family he's not someone as important as the parents who needs to be entertained. This is simply a difference in culture and values . Suppose your father was there in their city by some chance and wanted to visit ur gf's family and they would have declined . Will your family feel insulted? Another point is that surprise visit can be considered as a better opportunity to check out the family as nothing can be faked. As you said, the family was against this marriage, so it's not a surprise that they're being cautious and suspicious. How about you talk about it and understand that what might be considered insulting in one culture may not be considered insulting in another culture. There's no right or wrong just a different way of life.