Early one morning, when most American dogfighters were enjoying some hours of well-earned sleep, I was in a game where there were two different ###-named players.
They may well have been bona fide Koreans, for when I tried to address one of them in English, he answered only with tildes: "^^^".
Anyway, as Z has promised, the ###s were visible on the game screen.
But in the "Room" menu, where you go to see the names, ranks and numbers killed, these players had only rank and no names, as you can see in this screenshot!
Some days ago I saw another player who apparently had found a new way of becoming invisible. On the screen he had no name, but on the menu his name was a small x. Until now, he is the only one I have seen with this new kind of namelessness, so it may not become a problem.