So far as I know, he looks at it because he sits on the Board of Governors and it's convenient for him to look at it. But it doesn't really matter who looks and who doesn't. Voldemort knows about it, so he could easily send someone else if he had a mind to do.
I mean, it's not like Bill could casually ask his boss if he knows there's a book that inscribes the names of all magical children, can he? As soon as he mentions it, even if Mulciber didn't know before well - he would certainly know it thereafter!
Re: Private message to Padfoot
So far as I know, he looks at it because he sits on the Board of Governors and it's convenient for him to look at it. But it doesn't really matter who looks and who doesn't. Voldemort knows about it, so he could easily send someone else if he had a mind to do.
I mean, it's not like Bill could casually ask his boss if he knows there's a book that inscribes the names of all magical children, can he? As soon as he mentions it, even if Mulciber didn't know before well - he would certainly know it thereafter!