As XineAnn outlines in her O/P, when a member who is in one of your lists undergoes a change of rating (that is outside of your content filter) you should:
* not to be able to see the content of their pages (unless you choose to adjust your content filter)
* still have the opportunity to unsubscribe/unfollow (if you were previously subscribed/following)
* and still see them in your lists (albeit with a default profile picture, so that you don't see their actual, now possibly of an adult nature, profile picture)
This latter feature is not working curently, although I think that it has worked at some point since XineAnn first raised this topic.
We'll get it sorted.