Another mis-understanding it seems. I meant more along the lines that there already was a new entry in the "ForumSections" table, done from the admin panel, and that the script could create a brand new corresponding table to hold all threads for that section if it didn't have one related to it (Without the user knowing anything different). I was just saying that it would make more sense to create such a corresponding table at the same time as adding a new entry to "ForumSections" table in admin panel. This was just an example anyway, I'm not actually doing it.
Just a few milliseconds, huh? That doesn't sounds so bad.