Forcing a unique nickname

Hi there

I know the upgrade to 2.0 has removed filters, including the one I was using to force a unique nickname. I have looked into the new code and have now put the following into my functions file which seems to do what I want it to do (force a unique nickname). Although it seems to be working fine, can you see any reason why it might not in some circumstances?

Thanks!
Jon

add_filter('wppb_check_form_field_default-nickname', 'rf_force_unique_nickname', 11, 4);

function rf_force_unique_nickname( $message, $field, $global_request, $form_type_args ) {

	$nickname = $global_request['nickname'];

	global $wpdb, $current_user;

	//get user ID
	get_currentuserinfo();
	$curr_userid = $current_user->ID;

	//check if new nickname is unique
	$qtext = '
		SELECT COUNT(users.id) AS nickname_check
		FROM wp_[prefix]_users AS users
		INNER JOIN wp_[prefix]_usermeta AS meta ON users.id = meta.user_id
		WHERE meta.meta_key = %s AND meta.meta_value = %s AND user_id <> %d
	';

	$matches = $wpdb->get_var($wpdb->prepare($qtext, 'nickname', $nickname, $curr_userid));

	if ( $matches > 0 ) { //if chosen nickname is already taken
		$message = 'Unfortunately your choice of Nickname has already been taken. Please try another.';
	}

	return $message;

}

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