Move for Collections

I wanted to clarify my understanding of the MOVE operation for collection
resources. In section 8.9.2 "MOVE for Collections", it states:

   So, for example, if an infinite depth move is performed on collection /a/,
   which contains collections /a/b/ and /a/c/, and an error occurs
   moving /a/b/, an attempt should still be made to try moving /a/c/.

If the /a/c/ move is successful, what happens to /a/b/? I'm assuming we
would get the following result:

- collection /a/ and the /a/c/ subtree will be copied to the destination
- collection /a/ and subtrees /a/b/ and /a/c/ will be deleted from the
original location 

If this is the intended behavior, it seems to conflict with the atomicity of
the move method (copy then delete) on resource /a/b/: the resource will have
been deleted without being copied.

I haven't been looking at the WebDAV stuff for very long, so I apologize if
this has already been discussed or I'm missing something obvious.

Rob