Please find attached the statements from three detector concept
study groups on the push-pull option The WWS would like to 
add a few general comments:

The WWS thinks it is fundamental for the scientific program of 
the ILC to have two complementary detectors which create the support 
of a large HEP community in the world.  Without such support the ILC 
project would not be funded. We therefore believe that there is 
a serious risk in eliminating the 2nd IR unless the viability of 
the push-pull option can be convincingly prove. 

The opinion expressed by the concept studies are consistent with
'there is no show stopper for the push-pull option'. We believe,
however, that this does not provide a basis good enough to eliminate
the 2nd IR at this time. The answer to the question 'is there 
a possibility that the push-pull option will prove unfeasible?' is 
probably yes.

The ideal scheme for the HEP community which was intended in the
2 IR scheme was fast and frequent switching between two experiments
where there is little need for re-tuning of the beamlines so that 
there is no significant loss of luminosity. We wonder if sufficient 
resources have been used toward realizing such scenario.

We acknowledge that the push-pull option should be tried to reduce 
the cost, and great efforts from the concept studies went into 
this direction with however insufficient time to fully prove 
the feasibility. They are willing to actively continue their effort. 

Finally, even though we understand the tight schedule of GDE,
we are concerned that the push-pull option is already included in 
the IWA (Interim Working Assumption) upon which future design 
efforts will be based. The normal change control process
seems to be bypassed for this issue, and we worry that such 
short-cutting might result in a trouble later.