Well, if you can prebook the 100th post, it stands to reason that a prebooked 100th post doesn't necessarilly need to be made to the body of the thread to which it applies. It can be made anywhere at any time!

By George, this is exceedingly good news!

I do hereby declare that THIS post is, in fact, the 10,000th post to the Mother Of All BS Threads!

Hah!