public function get_meta_fields_by_event( $post_id ) {
		$fields = array();

		foreach ( Tribe__Tickets__Tickets::get_event_tickets( $post_id ) as $ticket ) {
			$meta_fields = $this->get_meta_fields_by_ticket( $ticket->ID );

			if ( is_array( $meta_fields ) && ! empty( $meta_fields ) ) {
				$fields = array_merge( $fields, $meta_fields );
			}
		}

		/**
		 * Returns a list of meta fields in use with various tickets associated with
		 * a specific event.
		 *
		 * @var array $fields
		 * @param int $post_id ID of parent "event" post
		 */
		return apply_filters( 'tribe_tickets_plus_get_meta_fields_by_event', $fields, $post_id );
	}