If you file a complaint with an instance like the NBA in this instance it will not go directly to the person who you complained about. They should stop the harassment.

In the case of accountants, the rules and regulations already make us write down a lot of our work and why we made certain decisions. If something is not written down, it is going to be hard to defend.

Yes in a restaurant it is different, but generally harassment is pretty rare, at least with the restaurants I have or had as clients. None really saw it as an issue. You just ban them, kick them out, call the cops if it really becomes bad or just deal with the couple bad reviews.