>I am worried about our operators accidentally inserting "library-1" good
>tapes (i.e. offsite) into the other "library-2" as scratch. The TSM server
>will add them to the "scratch" pool.

Bill - One approach is to apply solid-color labels to each cartridge,
       with a big sticker of that color around the library I/O portal,
and have like yellow for one library and purple for the other.
This would be an unmistakable clue to the operators, who would be very
hard-pressed to bungle that arrangement (and remain viably employable).
I'm not a big fan of having gummed labels applied to the surface of
tapes used in a robotic library, but I think the alternative is far
worse in your situation.

  Richard