I know the media we use are all pre-keyed on the media itself, so I never really paid that much attention to the keys.

I think I remember reading something about this a few years ago regarding SQL, but I can't find it. I remember reading it and thinking to myself that Veritas employed the same strategy for their BackupExec software back in the early 2000s. You could then apply new keys right in the software. As for SQL Server, I don't remember for sure.