I went through the database, and deleted all the posts from the beta site. Originally I thought we'd have to just go through the site and delete them as we found them, but they wouldn't allow deletion. And trying to find 220 posts in a set of over 65,000 is nearly infeasible.
The topics still show that there are guests having posted in them from the outside of the topic, but now you won't find wierd posts inside the topics. After the lan party I'll be working on a script to fix the Guest last poster errors.
(I should be sleeping, not working on tsn...I have a long day ahead. v_v)