the sending email address is ignored in determining is an email is junk. It is very very rare for true unsubscribed junk mail to keep coming from the same email address. Spammers regularly change them. usually from addresses like mine that are published somewhere on the web, or harvested from one of the app's on face book.

What I see are folks that want to be on web sites that requires a subscription to a newsletter expecting software to handle their decision to subscribe and not want to see the newsletter. In those cases you can use a message filter.