There are very few fixed points as far as group management, but this is one of them. It confuses me that you'd even want something lower than zero-access.
The idea is to place players in a
temporary "trial" rank with restrictions on tools and props commonly used by spammers, like FX emitters, dynamite, turrets, explosive and/or huge props. I've seen a pattern where spammers try using certain tools and props soon after joining, and if they're restricted they leave.
So if you can last a few hours on the server without finding the lack of those tools to be a dealbreaker, then the trial rank restrictions are removed.
So it would be like:
Trial guest rank -----[1-3 hours]-----> User rank
This was easily solved by just naming the 2nd lowest rank something other than "user" and assigning the user group to a team named "guest", but hopefully my way of thinking makes more sense after reading this post.