BuddyPress.org

I’m trying to figure out a way to moderate new users (why is this not an option?)
My solution is to not send activation emails automatically and then use a plugin that detects pending registrations and allows you to resend activation emails. that way admins can do some form of moderation.
I have placed this in my functions.php

function filter_no_activation_email() {

global $wpdb;

$user_id = $wpdb->get_var($wpdb->prepare( "SELECT ID FROM $wpdb->users WHERE user_login = '%s'", $_POST ));
$activation_key = wp_hash( $user_id  );
update_user_meta( $user_id, 'activation_key', $activation_key );

return false;
}
add_filter('bp_core_signup_send_activation_key', 'filter_no_activation_email');

This seems to work but is there any other way to get $user_id without having to query the database?

Or even better a plugin for moderation. looked around but there doesnt seem to be one