IMO what would be more a more useful feature (especially for those rendering from AVCHD source) would be to "shut down the computer when 'make movie' is finished". My take on how such a feature could work would be something along the lines of:
(a) A tick-box would be added to the "make movie" window, somewhere near to the "Start/Cancel" button.
(b) This tick-box could be toggled on or off by the user at any time before starting or during the "make movie" process
(c) If the tick-box was checked (enabled) at the time the "make movie" process ended the PC would shut down. However before shutting down Studio should display a "cancel" box for a few seconds so if the user is at the PC and doesn't want to shut down after all they have the ability to stop it.
(d) If the user did not cancel the shutdown, Studio would be closed cleanly and the PC shut down.
IMO just auto-exiting Studio and using another tool to shut down the PC is too risky; you'll alawys face the possibility of Studio taking longer to render than you thought and the tool shutting the PC down before Studio is finished
Regards,
Richard