Pretty much, and the potential for criminal activity is astronomical if you give them access to an open index. Things like every website on the web hit with the same zero day on the same day for maximum profit. Build your own best kiddie pron site evah! with direct access to the index and your own ranking system. What your admin pushed a config that left the admin pages open? Go time!

As someone who was operationally responsible for a search index (formerly VP Ops at Blekko) the kinds of things crooks tried to do was pretty instructive on how they use search in advancing their efforts.