"I want to hear what grue has to say about all this! "
I know you don't really but seriously
You share characters you pay the piper for any infractions of the person you share with, it's that simple. I cannot be expected to know that blog is John one time they are logged on, and Steve the next. When Blog cheats or pthieves, Blog and all of Blog's chars are affected. Know that and act accordingly.
There have been cases I know of personally where someone screwed up and then tried to claim it was a shared character when it wasn't. In the end no-one, including the immortals can rely on that. I can remember one case some time ago when someone hacked a character, sold all their equipment and stole their gold, and then claimed their son had used the char. All their chars still got wiped.
The best thing you can do is create a newbie, a few days later tarnsfer all you chars on in a way noone sees, never use the old chars again no matter what the temptation (people actually notice patterns of who logs on and rents). Build up the new chars and never let anyone know, and certainly never be naive enough to believe that at some later stage you can come clean and people will forgive you.
That's the reality. Trust is earned, not owed.