BuddyPress.org

I have been playing with the mU and buddypress and so far so good.
However with MU it seems I can only allow registration with blog creation or registrations only. Now I know from previous experience that I am am going to get bogus registrations so I don’t really want to allow blogs to created at registration time, as this will waste system resources if a blog gets created by the bots.
Is is possible to have it so that the registered user has to then login to create his blog if he wants one ?