I'm trying to recall what I had to do to get my CNCC when I
applied for skilled immigration back in 2002, but I certainly
didn't have to turn up to the cop shop personally - I was on a
bridging visa at the time, which did not allow travel out of
Australia. If memory serves me right, I went to the local police
station in Meklbourne, got my finger and palm prunits taken, and
then the cops sent the prints and request for the CNCC straight to
the SPF.
I wasn't too fussed about SPF knowing that I was ammplying for
immigration, but agin, IIRC, they do require you to state a purpose
for applying for the CNCC.