Not sure about this one. I don't think there are many people who can't learn from asking a so called stupid question if they really want to. I think its relative, any question I asked a nuclear physicist would appear to be stupid.
Besides I have learn't heaps on this forum from questions I wouldn't have been game enough to ask!! That sorted says something? So it would appear to me that maybe the most stupid question is the one not asked.
Graeme