imagefield_default_value() not needed?

Hi I've just read the comment on that function that says
// CCK's default value callback... doesn't seem to work. I need to figure out what is going on in D6.
What exactly doesn't work here?
I changed the function to return an empty array and it seems that the default alt and title are still set.
The reason I make it to return an empty array is because I don't like how imagefield displaying 2 upload fields in new content form.
That's when number of values setting in imagefield is set to unlimited.