> Which they can do with a FileOpenDialog, they can even select multiple
> individual files.
OK, I'm wrong again -- you can't use it to select directories

I wish it
could, seems like some lacking functionality.
But my basic point is still valid, I would use an OpenFileDialog to allow
the user to select exactly which files to use.
And consider this: if your application doesn't want to allow the user to
know what files are in use then I don't know why they should know and select
_where_ they are either.