From this thread discussing what to do about Mr Wilt's works:
…once a certain threshold of "undesirable behavior" is witnessed in a given user, the punishment meted out should not be magnified just because of the severity or magnitude of the behavior in question. Specifically, I'm advocating for that threshold to be "behavior that we don't want anything to do with whatsoever", and the limit of punishment be that meted out to Kondraki for his behavior, i.e. being not just banned, but shunned, having a lovely thread in 05 for people to read over later, and, if warranted, being reported to Wikidot et al.
But that would not include having their works summarily deleted. The precedent has been established (Kondraki) and seems to be reaching the same conclusion in another case (Mr Wilt). And I honestly can't see any such circumstances where we would summarily delete a banished user's work, absent plagiarism or other such disqualifier. I'm certainly open to tweaking/tinkering of the wording, though.