Haha this reminds me of an episode of Psych that I watched where Shawn asks Lassie if he is getting ready for the police man's ball and Lassie says that police man don't have balls, then Shawn says: "I honestly have no response to that."' Lol Supernatural and Psych are seriously my favorite shows of all time:)
I thought this was adorable the first time I saw it. Still do, but rewatching this episode recently I realized Dean wasn't with Sam when this happened, so Dean couldn't be certain what name Sam had given the cops. So by shouting "brother" he was saving them from a lot of explaining if he shouted the "wrong" name.