They're not that big of a deal. You all make spam bots seem like they're the end of the world. We don't have an auto security system because it was tedious for people who actually wanted to join our forums. We take care of them, you don't worry about them.
We've had security steps to not allow bots to get in but that would also cause new people to not be allowed in and the auth going through 300 names to approve or deny membership an hour