I lived in SF for ten years - before I moved to NYC/NJ i would always complain here about my experiences as a black man.

when I lived there I was always the only black person in the room, my black friends who were residents were also always the only black face in a room.

That said, I don't trust the black person among white people who lacks any connection to blackness, i.e.

- code switching when it's just us, you don't have to sound like you're from the block, but even Obama throws a bit of flavor in when he thinks its "just us". Imagine, Bryant Gumbel in a wave cap type energy.
- the head nod
- acknowledgement of racial inequality via the latest public display of racism - "whadya mean overpoliced?"

You can be the most isolated from black culture black person, but I can tell within 30 seconds if they will be down for it or not.

Think of that moment in Get Out when homie saw his friend at the party. THAT'S THE VIBE I pick up on.