At this time there are performance and cacheability impacts of blocking members everywhere that preclude us from doing this. In the future we would like to address this better.Paul Rankin commented
The following CSS will block a single user, replacing their name, reviews, lists, etc. with "Blocked User" and their avatar with the generic Letterboxd image (replace "lordcookie" with whomever you wish to block):
You can use this via GlimmerBlocker or in your browser custom stylesheet. Unfortunately, you will need to duplicate for each additional user because my skillz are not tiptop.
129 votesPaul Rankin commented
I second this. Or better yet: don't include collections at all. Putting the three Lord of the Rings movies in a box together does not create a new film.