Another scenario: A remote minion is ordered to fetch the backup tape out of the tapedrive. She goes to the rack and doesn't pull the tape out of the tapedrive... but 2 (two) HDD's out of the drivebays at the same time and voila: 2 drive failure.
You think this is far fetched? Well I'm at a customer now who did just that and is now looking at a server rebuild.
Good thinng she didn't burn the tape that was actualyactually in the tapedrive or whatnot ;-)