So ... funny story there. There is the concept of the "N-word pass" that black kids will "give out" to non-black kids "allowing" them a use of the n-word in front of them. I had heard about this several years ago, but now several of the black kids in my son's school are giving them out occasionally. I advised my son to never use the option were he to receive one!
Not a physical card in this situation, but there are stories that some kids in other schools actually give out physical cards.