A couple remarks...

I spent about 30 minutes to delete 10-something Joey-threads. If someone decides to spam the forum with more than 20 posts, there's nothing I can do about it (I'm not gonna waste an hour clicking some buttons). Something else: deleting threads makes AO laggy... I opened ten windows to delete the threads at the same time, and I'm pretty sure surfing AO wasn't much fun for most users on that moment...(although AO cut off my connection after a while).

Although your suggestion would prevent things like that, I think the effort to make it that way isn't worth the end-result.
Here's how things are now: people posting copy-and-pasted tutorials without quoting the source won't get away with it, as we've seen in the past. Crappy tutorials are either deleted, or negged to death. Posts that don't belong in Tutorials are moved.
Implementing your suggestion would save me some time, but I don't think it's worth the effort. If Joey wants to spam, he'll just do it on another forum anyways... There's plenty of forums that aren't moderated (funny enough, there rarely are spammers on those forums).

Last thing: there's a 'report'-button