From 157.2answer, last paragraph:
If a user tries to post to the community after these limits have been reached, they will receive one of these error messages, and the entry will not be sent to the moderation queue or the community.
This seems to imply that if the queue is full, even entries from users who can post unmoderated will be rejected, which sounds weird. (But that could be how it works. I haven't tried and I'm in the middle of translating that FAQ, so I don't want to dive into the code. Hence the [comms|doc] bit.)
I suspect that it should say "to the moderation queue *for* the community" (that is, that unmoderated posters can post even if the queue is full). But if I'm wrong, perhaps changing it to "to the moderation queue or *to* the community" would make it clearer to translators, if not to users overall.
So, those knowledgable about community moderation queues and/or people who want to test things, what happens when the queue is full and an unmoderated poster (and/or maintainer) tries to post? I think the post goes through but I don't remember. (If no one knows off the top of their head, I'll probably post to support_testers or lj_volunteers.)