A better solution would be making a new forum called “Newbie Help”, and give lv4 access to everyone there.

Meanwhile, to access the other forums your account must be active for a week (if you think a week is too long, make it 4-5 days). Make that the same for INCIT and buildrs.

That would not scare away dedicated trolls, but not only it would prevent instant forum posting, but it would also kill most of the illegal multis that are created for the sole purposing of upvoting/downvoting.