Tapes Always send tapes in cases. When tapes enter the dubbing queues they are stacked. Caseless tapes do not stack well. Caseless tapes will will be returned, udubbed. A second offense will result in revocation of Library Dubbing Services privileges.
Most dubbing problems are directly attributable to improperly labeled tapes.
Label your tapes properly. Label the spine of video tapes. Label the A side of audio tapes. Do not label the B side of the tape unless the B side calls for a different selection. The label serves not only to identify your tape, but as a visual clue to allow the Librarian to easily differentiate between the A and B sides.