Obviously you are Chances that you will be caught with just 1 post are zero
, so the example doesn't mean anything. I still haven't heard 100% who the double account was, only guessing, so it's impossible to say anything conclusive really. Previously banned accounts never come back as positive posters, otherwise they wouldn't have been banned in the first place. If they come back, it's usually to troll more/harder.
No. There was a recently banned poster whose DA had 0 posts and she was still caught and banned for 3 months. I don't know if it's right to reveal her name here, but it did happen, simply because she had a DA
In that case they should be banned again, but not because they're DAs, rather because they are bringing the forum into disruption with their posts.