I have seen instances where vias or copper under certain components contributes to defects during manufacture - poor paste application, component movement during reflow.

There are also some component vendors which suggest not placing any copper under their devices.

I have also had requests where having all features accessible on a fully populated assembly for potential rework was a customer requirement.

None of these really seems to fit into the situation you are describing, appears your customer may have been burned by poor manufacturing / fabrication in past and is attempting to avoid addressing the real problem.

Hth,
Dave
> 
> From: DesignerCouncil automatic digest system <[log in to unmask]>
> Date: 2009/03/18 Wed AM 11:00:08 CDT
> To: [log in to unmask]
> Subject: DesignerCouncil Digest - 17 Mar 2009 to 18 Mar 2009 - Special issue (#2009-51)
> 
> 

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