fedi idea: what if there was a kind of middle step between "sign-ups need to be approved" and "anyone can sign up and start posting"?

like maybe "anyone can sign up and start posting, but until your account is manually approved, your posts aren't sent to other servers and you can't follow/be followed by people on other servers". (basically, forced local-only; see e.g. Hometown, a Masto fork with local-only posting.)

it would certainly cut down on the reach of spammers/scammers.