I know that this is not a democracy, and I'm not a mod, so my opinion probably doesn't matter, but as someone who has been posting both on the site and forum regularly for about five years and has been friends with you both for even longer, I'm going to share it anyway.
I'm a teacher, in back-to-school mode, so that's the lens through which I'm looking at this whole issue with the rules. It's important to have rules on a site/forum with this many different people posting, just like it's important to have a rules in a classroom.
In my classroom, the kids and I make up the rules together on the first day of school. We brainstorm and come up with maybe three basic rules that cover everything and that everyone can agree on, and we write them on a poster that we all sign, and it goes on a the wall as a reminder of the rules. We go over those rules whenever it seems the kids need a reminder.
When the AC rules changed back in November, they changed based on problems that were happening on the site (spamming the Most Recent page, lots of unedited fics, and so on), complaints from readers who just wanted to read a variety of well-written stories, and certain users who were finding ways to get around the old rules (creating alter egos to be able to post more and review their own stories, etc.) Like Mare said, we were given plenty of warning before the new rules went into effect, both on the site and the forum, so at that point, no one posting on either of those places should have missed the new rules.
It's been nine months since then, though, and we've gained a lot of new users or old users who have come back from long hiatuses, not realizing the rules had changed. In my classroom, when I get a new student, I make a point to go over the classroom rules with them. On a site, you can't exactly do that; it would be ridiculous to expect Mare and Julilly to contact each new member to make sure they understand the rules. It's the members' job to actually READ the rules before they post. That's why the rules are there on the site, and they're now updated to be consistent with the rules posted here, so that issue has been resolved.
Still, seeing as how we've had this issue twice in two weeks now, with older members who have come back and accidentally broken the rules, it's clear to me that people aren't reading the rules carefully enough before they post. Is that the mods' fault? No. Is it the users' fault? Yes. Should they be publicly called out for it and banned for a week without warning the FIRST time it happens? I don't think so.
Going back to the classroom, I would never write a student's name on the board and take a week's worth of recess away for one small misbehavior. The first time they forget to raise their hand or clean up the floor under their desk or hand in their homework, they get a warning. "Next time raise your hand." "Please pick up your papers." "Turn it in tomorrow." The second time it happens, then there's a consequence. I believe in zero tolerance for some things, but only very serious things - weapons, violence, bad language, bullying. I teach children, and children make mistakes. Adults make mistakes, too. I think it would be great if everyone had a safe environment in which to make mistakes and learn from them without being humiliated.
My point is, I think a one warning system would be a fair revision to the rules of this site. It would prevent people like Sarah and Karin, who made an honest mistake, from being made to feel bad because of it, and I doubt they'd make the same mistake twice. It would reserve the serious bans and appearances in AC District Court for the people who really deserve them, the ones who flaunt the rules and break them more than once. I think THOSE are the people the rules had to be changed for, and those are the people who should be punished for breaking them.
This is just my opinion; like I said, I know I have no real say in the manner, and if you're not open to change, you're not open to change. It's just a suggestion that might make things a little more comfortable and fun for people again.