How about just banning him from your board completely?
If a user misbehaves at point X, I'd rather get him or out completely before he starts messing around also on other points.
The reason I'm not banning is that I have a subscription area of the site for ads, promotions, etc. so I'm trying to steer them to post there.
I have now created a new group with limited access and full post moderation that I will put these users in.