"if you set the output volume to 0 it also set the tape-to-tape volume to 0"
Ugh, very ill designed - did the volume also controlled the gain? Probably cheap model used simple circuitry with such limitations.
Anyway, I never dared to put a data tape into my hi-fi for fear of damaging it - it was my fifteen birthday present (Technics turntable, Yamaha amplifier and cassette deck, Epicure speakers), it was expensive, I wasn't going to risk it in any stupid way - I couldn't ask for another.
Especially since my father still believes I deliberately killed his older (end of '60s) turntable/amplifier system to obtain the new one. I was just happy when it died because of its age.