The issue is not entirely the hole itself but the entire hole feature
includung any pad(s). When the edge of the board is routed, it is
generallly a good idea not to clip the hole or expose the copper pad
area at the edge of the board. This plays into the ongoing debate over 
fabricators removing pads in that the internal layers may have non-
functional pads which may be exposed throughout the entire package
stackup - probably best left to a different forum - but we have always
tried to prevent such occurances. Keep in mind that common sense often
is a good guide and that in most cases exposed copper at the edge of a
PWB is not a good thing.

Regards,

Bob Hoene
Marquette Electronics
Molwaukee, WI