Apparently you can still see the tags and comments on blacklisted posts when looking from the Comments page. That is sort of silly, so I wrote a little script to stop it.
http://userscripts.org/scripts/show/101056
Note that I don't use a blacklist myself, so if this suddenly breaks, I will not know to fix it unless you bug me about it.
Also, there does not seem to be a help:blacklist or equivalent, so the useful threads index may be the best place for this so that people can find it.
Updated by OOZ662