have you enabled the newly registred user thingie too?
you can find it somewhere in the board settings i think.
there is a minimum count wich is by default set to 0
when that is set so something like 5 wich is the value at sapph then users become normal users as soon as they reach that value
that newly registred user thingie is also a user group wich can get access restrictions.
i've as example set it so that they can never post without approval
seem to work so far. they got nearly the same rights as users but need to get approved.
also i've denyed them to vote in polls.
same for guests. though guests have even more limits in sapph. they can as example only post within the guest forums there wich is "unban requests" and "ask a question"