Joao sez, "As soon as I saw Smartfilter's bots snooping around I blocked their IP ranges (fight fire with fire)… Looking at my logs it seemed to have worked, since people still access Boing Boing through my Distributed Boing Boing. My .htaccess, may be useful for anyone:"
DirectoryIndex dbb.phporder allow,denydeny from 66.45.10.64/27deny from 206.169.110.64/27deny from 192.55.214.0/24 allow from all
(Thanks, Joao!)