You get banned when you repeatedly break the rules. You can find the rules in the TOS.
Before anyone is banned, they receive warnings. If they continue to break the rules after being warned, they get banned.
Not all bans are permanent. Some are temporary.
Further, the moderators and administrators privately discuss and agree upon bans before they are given.
Being a longstanding member or having a high post count does not exempt you from the rules. If you break them and ignore warnings, you will be banned.
Bans are not discussed publically or with anyone other than the member involved. They are a private matter between the member and the Head-Fi Staff. The point is not to publically humiliate anyone.
If anyone has questions about the rules, feel free to send me or anyone on Staff a PM. We are happy to answer your questions.
I am closing this thread because we do not discuss Head-Fi's administration in public forums. I will leave this thread up as information. Again, if you have questions, please PM a Moderator or Administrator.