Although this feature should be implemented in a very late stage of the development, thoughts regarding security need to be done already now.
It is advisable to "force" joe user to update his system if security fixes are out, else BeOS/Haiku (and I know, Zeta developers are reading this thread, too, so this message addresses you, too, yT :) ). The system should download __and install__ security updates as soon as the user is online.