[quote=Savato]
Because Naruto totally knew Nagato beforehand. Yet they descend from the same clan. I guess it depends on the backstory? Because ya' know, if the clan is divided or some have been on their own for a long time, would make sense that they're strangers to clansmen who never met them before they've left.
[/quote]

... Naruto and Nagato were from two different villages. That example is completely invalid for this case. Naruto didn't even know who his parents were until he reached a certain age.
I'm talking about in Konoha. -.-