I’d also welcome a solution that the first few posts are somewhat restricted. For example, if you have a post count below 10, allow the start of only one thread every hour. Should be enough in the beginning.
And then, would it be possible to implement a solution, that if a thread of someone in this restricted user group is flagged as spam (maybe by two or three people in the unrestricted user group in a short time), it will be unpublished immediately and marked for moderation? This forum is pretty civil and I’d think abuse of this function would be low to zero.