Mods and VIPs can see deleted posts so that really isn't an issue. Also there is a mod control panel to see unapproved posts and those awaiting moderation.
Personally this is what I would do myself.
1) If post is in violation of the rules, but not too inflammatory, I will delete it. If it was very inflammatory then I would post in the thread as a warning.
2) If it was posted a 2nd time, I would message via PM for a final warning and delete the post again.
3) If it happens a 3rd time, I will request a ban since I can't do it myself.
I think this would get around the double post = ban situation that apparently exists.
Oh and in the spirit of moderation: Campbell, it's apparent you have a problem with PSPOwnage. There is no need to harass other members in any thread if you have a problem with him. If he annoys you so much, just put him on ignore.