I have seen a couple of websites (mostly forums) that had a small area (e.g. subforum) where moderation was intentionally limited or completely absent. This is usually done to allow people to let off some steam, and allow them to fight their fights in public if they really feel a particular desire to do so.
In one particular case -- an enormous gaming forum -- I remember that this subforum caused immense issues when people used this subforum to publicly insult the administrator, his wife, his children, as well as other moderators and their family members. Even though the rules strictly said that this was allowed, the subforum was closed in the end, and dozens of people were banned from the website.
The question: could/should the administrators and moderators have seen this coming? Is there some way to "keep the sharks at bay" in such a zero-moderation area, so that it does not end up harming the community itself?