Your post triggered a very faint light in the cobwebs of my mind.

I seem to recall some additional functionality of the NTFS that is not well documented (of course). Each NTFS file has something called an "alternate data stream" (ADS). Here is an excerpt [link|http://patriot.net/~carvdawg/docs/dark_side.html|from one] of the over 9000 articles Alta Vista returned when asked for "NTFS and stream"
NTFS is the preferred file system due to its stability, functionality, and the level of security it provides. NTFS alternate data streams (ADSs) are provided for compatibility with the Macintosh Hierarchical File System (HFS), which uses resource forks to maintain information associated with a file, such as icons, etc (RUSS00). While Microsoft provides a means for creating specific ADSs via Windows Explorer, the necessary tools and functionality for detecting the presence of arbitrary ADSs is conspicuously absent. Oddly enough, the operating systems have the necessary native functionality and tools to allow a user to create ADSs and to execute code hidden within those streams. Microsoft KnowledgeBase article Q101353 acknowledges the fact that the Win32 base API supports ADSs inconsistently. [emphasis added]

An NTFS file created with a stream other than stream 0 would appear as a file of 0 size to a program, but would (probably) not be visible to the Explorer. It appears to be possible to create a directory containing only ADS's too (but I'm no expert on this). It seems as iF A and B may well be such entities.

HTH