I am afraid YOU missed the point entirely. This is a story, the same as any book. The characters in the story don't get to just 'leave the story' temporarily just cause someone they don't like is on. No, they get beat on, battered, bruised, trashed, destroyed, humiliated, or do all these things to the other person.
They talk to one another and try to resolve the conflicts with some semblence of reason. They don't get to bail out and just quit when something is happening they dislike, or when someone they dislike comes around... What kinda piss-poor story would that be?
By trying to make a person 'cease to exist' or doing the bb/qq thing every time you see them on, you are removing an important piece of YOUR roleplay, namely, how you interact with 'evil', 'bad', or otherwise 'undesirable' characters.
You are, in effect, making your character flat, dull, boring, and otherwise just a bad character. You know, the kind you kinda skip over in books and movies? Yeah, one of those. The only way to remain interesting as a character is through conflict. In Avalon that almost always means the people on the other side
Written by my hand on the 22nd of Leaflost, in the year 1257.