For purpose of the quesition, I am going to paint a picture:
A system administrator maintains and backs up a production server for clients with sensitive financial information (account numbers, names, SSNs, etc). The machine is a Windows 2003 R2 64-bit Itanium server with Backup Exec 13d as the backup solution. The backup rotation is a full backup on a 3 week rotation unencrypted using LTO3. One tape a week is transported to another location for disaster recovery purposes.
What if the tape gets lost in transit?
Aside from the PR issues with the clients having to disclose that their information has been displaced, what is the actual likelihood that useable information for the purpose of identity fraud could be abstracted? I paint the picture above because from the point of view of the finder of the tape there are a lot of unknowns (aside from the label of what day the tape is backed up on). This backup could have been from an *nix system using bacula on an IBM Power System for all they know. The only thing they have for sure is the type of tape from the labeling. Aside from that, where would somebody with malicious intent start?