I am seeing a burst of GET request for archive date out of range of the Blog History from muliple IP address then a burst of activity from these IP addresses.

Is there a way to create a 404 Error for future dates or dates before the first posting for the blog (if you wanted to be bad just hang the socket open some random time value. Slow down the number of sites they can scan per minute and it is likely they will drop you like a hot rock)? At present the code (b2evolution 0.9.1) is returning a "200" and a "sorry no post" page. They appear to be using this method to identify what blogs can be probed deeper.