If I ain´t remembering it wrongly now (it was a while since I last played a MP battle though), so is the rules written at the top of the message window in the chat lobby. Unfortunately these rules quickly disappear out of view when messages starts to appear.
Regarding your idea of a automatic email, sounds quite good in my ears as well. That would save a lot of work regarding having to reply to all these "Why am I banned?" questions!
//Zeke Wolff, Moderator.