COPY and bindings II

A while ago I asked, whether - assuming no resource at destination to
overwrite - COPY should preserve bindings, i.e. should COPY yield 1) or 2)
(see below):
1)
      |u1     --COPY-->    |u2
      C                    C'  
    a/  \b               a/  \b 
    C1  C2               Ca  Cb 
    x\  /y              x|    |y
      R                  Rx  Ry
2)
      |u1     --COPY-->    |u2    
      C                    C'  
    a/  \b               a/  \b 
    C1  C2               Ca  Cb 
    x\  /y               x\  /y
      R                    R'
Most of you voted for 2).
Now, assuming there *were* resources at destination to overwrite - take
diagram 1) for visualization, where C', Ca, Cb, Rx, Ry all existed
beforehand - I assume that COPY u1->u2 would result in Rx and Ry both being
updated with content + dead-properties from R.
And, again using diagram 1) and assuming all shown resources existed
beforehand, what happens if we do the COPY the other way round, i.e. COPY
u2->u1? The Binding spec states in section 2.3, last paragraph:
"If a COPY causes one or more existing resources to be updated, the bindings
to those resources MUST be unaffected by the COPY."
Is it then correct, that while copying the C'-tree over the C-tree, resource
R is first updated by Rx and then again by Ry (or the other way round)? That
is, one of Rx or Ry "wins" in updating R? Hm???
Regards,
Peter