Basically to keep it real when you are black.
But it can be considered revoked if you do otherwise. For example be black, but a Goth or Punk (musical sense)
It's a common joke that then it is revoked, to turn it in at the nearest liquor sto on Martin Luther King blvd, and turn it in. Also you can do so at Roscoes Chicken & Waffles...
Man, her 'black pass' is REVOKED!
If me and my friends were screaming and yelling on the bus, we would have been kicked off, but those black guys can do what they want because they have a black pass.
Black - a color, actually all colors combined.
Pass- a type of permit.
Black Pass - A dark permit.
An allowance of all things colored?
I don't know.. The example shall speak for itself.