If a user has, say, asked more than 20 questions and more than half of those have been closed, shouldn't there be some sort of penalty (such as not being able to ask any new questions until some number of the closed questions are improved or deleted)? I understand that it may take some new users several attempts to grow accustomed to the format of this site, but there have been some users recently who seem to simply refuse to learn...
I'm fairly certain I know which user you're talking about, and yes they are ignoring community members, vandalising their own posts, and generally polluting the site with awful questions.
There is an automated system that bans users after some criteria or other is met, but the algorithm is not public knowledge (even to mods) so that people can't game it. Since originally writing this I've learnt this isn't implemented on Drupal Answers (thanks @kiamlaluno).
I'll keep an eye on it, have a chat with the other mods, and send a friendly poke to the user if their 'behaviour' doesn't improve.
The potential penalty is a ban until the user takes notice of the community's concerns, but I'd much rather that was used as an absolute last resort.