Selecting a valid folder + a valid file actually results in the file dialog opening the valid folder (if the folder is selected first).
Perhaps mIRC could mimic this and return an empty list with $sfstate returning "error" if the reserved/Fonts folder appears first in the list of returned filenames.
But if the first filename being returned is valid, then removes any reserved/Fonts folders from the list.
That would handle the case where "Fonts" is the only item selected (by returning empty list + $sfstate set to "error") as well as allowing valid filename to be returned if a valid filename is selected first
