Gonna try and address the original poster's question and follow up info. Since we are in the 'Politics & Philosophy' forum that is how I will approach the questions, practical matters of protection have already been addressed. This represents my personal interpretation of Burning Man, I have absolutely no official capacity.
Radical Inclusion
Anyone may be a part of Burning Man. We welcome and respect the stranger. No prerequisites exist for participation in our community.
Radical inclusion is defined in terms of accepting new and different people not in terms of ignoring the past. To exclude your scary person from your experience does not violate this principle in my opinion.
Obviously the term 'inclusion' is usually used in a much broader sense. In the broader sense of 'radically inclusive' I would say that all people are welcome to the event regardless of race, class, politics, sexuality, or criminal history. It means that there can be theme camps devoted to violence, peace, sex, drugs, Jesus, Buddha, or any other of a variety of potentially offensive topics. This does not mean that you as an individual need to hang out, camp, or spend any time at all with an another individual who you don't like for any reason.
I would suggest that avoiding someone with a history of violence towards you would be an act of radical self-reliance, another of the ten principles. Notifying your camp-mates and friends, the rangers, local law enforcement, and other playa organizations would be acts of communal effort and civic responsibility, two more of the ten principles.
Burning Man is not
other than the real world, it is a
part of the real world. A very special part for many of us, but not so special that you should feel compelled to put yourself at risk.
Ten Principles
Survival Guide: Safety There is a paragraph about personal safety half way down the page, it does not contain much practical info, but it illustrates that taking care of yourself is part of the deal.