The Profile, Wiki, Favorites, and Comments pages do not respect a user's blacklisted tags setting. This forces it to happen. If an image that appears either in one of the examples on a wiki entry or in the comments tab is tagged with something in your blacklist, it will now be hidden.
For images on favorites pages or either in the Uploads or Favorites sections on a profile page, it will hide thumbnails with tags that you have blacklisted, but only if it is someone else's profile, or anyone's if you're not logged in. Because it doesn't make much sense to hide thumbnails for images you yourself uploaded or favorited, even if you have since blacklisted a tag it matches or such a tag was added to it, for obvious reasons. And yes, you can blacklist tags without logging in.