We recently had a problem at a prominent client. Many (near) duplicate records were deleted from a critical table. The client IT manager could not use his "agent backup" to restore the backup to a different database on the original server. He had to restore to the same database name on a different server. The backup worked though.

I have often said that the way to test backups (SQL or otherwise) is to:

1. Perform the complete back up from A.

2. Use the back up to restore to B.

3. Compare B to A.

In disaster recovery A is gone anyway.