I can only speak for what I personally did and witnessed in the 76 - 80 era of HF Contesting.
I never, nor saw anyone ever, logging unanswered CQs in a contest. Simply the call, exchange, and the infamous "Dupesheet". Back then there was a real reason to have 2 ops tied into a run frequency, one operating and one logging. It wasn't that it was hard to log at all, the issue was also filling out the dupesheet so you could see if you worked someone on a band.
I can remember the screams of DUUUUUUUPE from behind me to this day.
Ed N1UR