@Don There should be a section in your forum rules which lays out "How to ask a good question". Perhaps you can borrow from StackOverflow.
While at it, I wonder if you could remove the threat of banishment brandished even before admittance to the question input dialog. The carrot should be the chance of an upvote for a good question, the stick a downvote for one that doesn't meet the standard. Voting is the community's way of expressing its opinion, banishment the owner's last resort not against those who post for the first time but repeat offenders.