calls to be made (if eg. mounting "D:\foo"), causing "volume not ready"
dialogs. This happens with removable devices like memory card readers
that don't have a device.
I think this is generally incorrect: if a user has a memcard reader, we'll ignore
it on the first change (no device is installed), and then we'll never actually
notice when a card is inserted, since the drive letters don't actually
change. I don't have a memcard reader to test this, so I'm punting on
this for now.
Chris Danford