I agree with D Rooke who said:-
 
>In my experience, in cases where non functional pads have been removed,
>it has been to allow the routing of tracks closer to the holes than would
>otherwise be permitted should the non functional pads be present. Such
>design rules often neglect the reasons for having a pad larger than the
>drill size in the first place.
 
We had problems with non-padded holes as close as 6mils to inner layer tracks. 
It was not picked up on CAM MRC's because we do not have a hole to nearest 
copper check. We fortunately picked up the error during inspection of the 
photo-tool and it took a lot of time to re-rout tracks and move holes to give 
the required manufacturing clearance. Non functional pads are useful in 
preventing this at the design stage and can easily be removed by the 
manufacturer, with permission of course, after he has carried out his MRC's.

Non functional pads should be removed from inner layers, particularly on ground 
plane layers where there is say a 10mil annular clearance around a pad which is 
difficult to fill . We use vacuum but without it there could be air entrapment 
particularly on 2oz layers. It also makes inner layers more difficult to inspect 
and can increase incidence of inner shorts. No pad, no problem. It also helps to 
improve drill life.
  
Paul Gould
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