re: Hybernation vs shutdown

I suspect that the system shuts down the computers rather than hybernating them so that the users are also logged off and their IDs get uploaded to the servers which will be backed up.

Also, if you are going to the hassle of writing software/scripts to do this, you may as well shutdown so that each day gives you a clean 'just booted' OS. This can be very helpfull in a dodgy bespoke software environment where memory leaks are aplenty.