Users are not able to access contents of folders where they do not have permissions to access all folders preceding them in their path via CIFS. Via WebDav users are able to access folders they have permissions for regardless of permissions on parent folders.
Create nested folders Company Home/L1/L2/L3/L4
Remove permission inheritance on L2 so that no users are explicitly allowed access
Grant access to a user 'test' on folder L4
Via CIFS direct access to L4 will not be possible as tested in Windows 7 and OSX 10.7:
Via WebDav Access to L4 will be granted but attempting to access the parent folder results in a permission error:
Permission behavior consistent between access methods.
Permission behavior not consistent between access methods.
This could be the result of the CIFS protocol specification specifying that permissions on each path component must be checked although to my knowledge this is not the case.