Edit: sorry for waking a necrothread. I was unprepared for how stale some posts are in this community.

Don't forget: all those discs have a "write protect" switch on 'em! Can't be too careful.

In reality, it's sometimes appropriate to set the bar at "tamper evident". Basically: did someone fuck with the data while nobody was looking? If the goods are just missing, or the enclosure is forced open (breaking it), you can reasonably answer that question.