David,
I have DRM and it really helps but even then I wrote a lot of stuff for the
offsite movement.  Mainly because I needed something that looked more like a
mainframe.  TSM is designed for open slot vault management.  That is a bear
especially when you consider the 3590K media gets destroyed if it is dropped
at all.  So, we put our tapes in sealed cases and do move data commands to
resend the data offsite the week before the tapes are coming back containing
that data.  Yes, it takes a lot of hardware to do that, but it is definitely
worth it to know your tapes have not been monkeyed around with.