Isn’t possible at the moment.
My site is getting heavily brigaded by spammers
Sorry for you, but adding moderation to status wouldn’t avoid spammers signicantly.
Have you installed WP by following some basic security recommandation ?
Do you use some anti spam plugins ?
How many members do you have and to what do you estimate the amount of spammers in regard of them ?
Have you inactive users in the list ?
Are you on a MS or single install ?
Maybe you could also blacklist some words from updates publication.
