Here is the next release, that optimizes moderation queue usage in the product. Guest-posted threads/replies will not be any more added to the moderation queue. The threads awaiting for registration will not be visible in the thread list to moderators at all and will be listed only if the user registers.
We have also modified the way unregistered/unconfirmed users are handled. If a user does not register within an hour, their thread/post is deleted. If a user registers, but does not confirm the email address (most likely meaning a spammy registration from a non-real email address), their thread/post and user account gets deleted after 24 hours.