bbp_suppress_private_author_link( $author_link,  $args )

function bbp_suppress_private_author_link( $author_link, $args ) {

	// Assume the author link is the return value
	$retval = $author_link;

	// Show the normal author link
	if ( !empty( $args['post_id'] ) && !current_user_can( 'read_private_forums' ) ) {

		// What post type are we looking at?
		$post_type = get_post_field( 'post_type', $args['post_id'] );

		switch ( $post_type ) {

			// Topic
			case bbp_get_topic_post_type() :
				if ( bbp_is_forum_private( bbp_get_topic_forum_id( $args['post_id'] ) ) )
					$retval = '';

				break;

			// Reply
			case bbp_get_reply_post_type() :
				if ( bbp_is_forum_private( bbp_get_reply_forum_id( $args['post_id'] ) ) )
					$retval = '';

				break;

			// Post
			default :
				if ( bbp_is_forum_private( $args['post_id'] ) )
					$retval = '';

				break;
		}
	}

	return apply_filters( 'bbp_suppress_private_author_link', $retval );
}