We designed the Multimedia Center at Northwestern University (24 individual
viewing carrels ) in such a way that all cables are "buried" in hidden
access panels and thus pretty much out of sight and inaccessible. Sounds
like it's too late for you to do that, so if I were in your position, I
think I'd try the following:
1.Hold student ID's at the main service desk and tell all users that you
will have to check the carrel when they are finished viewing before the ID
is returned. You don't actually have to do this every time, since just the
possibility of it happening should suffice.
2.Go to a local print shop and have professionally printed warning signs in
red ink stating "WARNING: Tampering with AV cables in this carrel will
cause alarm to sound" (or words to that effect). Of course there's no real
alarm, but once again, the bluff should suffice.