Sorry, no. Only workaround are to let the user something is installing by enabling the progress bar option, notify user option, or making the package on-demand. The first 2 options work great when someone is logged in. There's a very small chance that someone shuts down the machine at the login screen when the package is installing. Obviously the progress bar and user notification options only put up something to the logged in user and not when the system is at the login screen. On-demand on the other hand is good for optional packages but not so good for things like security updates that you really should be forcing down on the user's computer since some users may never go and initiate the installation.
can this be made a feature request?