Okay, I just reread all the forum rules. I agree with 95% of it, but there are two things that stand out.
1. Moderators can ban users for any reason. This just leaves the door open to abuse. For example: I was once in a conversation with a mod that was not going very well. I decided to end the conversation, and said goodbye. What response did I get in return? "DO NOT REPLY AGAIN OR YOU WILL BE PERMABANNED!" It's like the mod in question didn't understand the concept of "Goodbye."
2. "Note that this is not intended to be an exhaustive list of everything that a user can be punished for."
This is fine and all, but I really think a warning message should be sent by the mods first. I don't think it would be fun to wake up to a ban saying "You broke this unwritten rule, so you're gone from the site for five or six days." Also, if somebody needs to be moderated for a rule that has not been written, then why not work on spelling that rule out ,and adding it to the list of rules? That would be an awesome help for people looking to avoid moderation.
Simply put, repeat offenders won't get the same sorts of Warnings if what they're doing continues to break rules, but they are more guidelines than anything else.