The former, with references that try to handle the pagination problem with explicit text of the form "on page X" (which implies that we are *not* on page X right now - but this is impossible to find out until very short before completion [well, not with (La)Tex - I think there are tricks around which change the text depending on whether something is on the same page or not ..).
But it's a minor point - I won't hold it against a book (only its typesetter :) ) if there are such "same-page references".