Option five: a glitch. I'm not saying that's what it is, but I had a friend who would almost continuously have the d/c icon next to his name, especially in any dungeon or trial, even though he was never d/cing. Oddly, for him, it ended being a graphics card driver thing, which makes no sense but... Anyway, the point is is might be nothing other than a minor glitch. Of course, it could be aliens.