Please note that items that stop being visible on Internet Archive, do not get deleted just "darkened", that is, hidden from the audience but still stored by the Archive. This is especially true for items hidden for copyright related reasons, but might be true also for spam to some extent.
I'm also certain that if a user account gets disabled, items uploaded by that user are not deleted just darkened, or they even might be still visible, just not tied to a user account.
Hiding certain copyrighted content is an obligaton of the Archive, in order to avoid lawsuits.
It is not advised to mass-upload "blatantly copyrighted" content, but if it's some rare thing, endangered by disappearance from the web, you are definitely encouraged to upload that. In case of a larger, related dataset, or if you think that the copyright owner will get it taken down, you may however contact someone from the Archive, e.g. Jason Scott (SketchCow on IRC) who can create a dedicated collection for you, and as he's noticed about the content, you don't risk getting banned.
Keep up archiving, but cooperate and communicate when necessary.