Dovster I am sure it's not the same today as it was 42 years ago. Your question reminded me of this story. It would be interesting to find out as it seems all airlines are getting very strict as they need the dough badly.
Now another little story from the old days. In the old days El Al did not always follow the IATA rules. All airlines had to offer "the same fares" as these were the IATA regulations.
My father was given a nice discount in 1962 on 4 London to New York tickets by the LY Milan office. The Manager went and told someone and LY were reported to IATA. The poor guy got fired and EL AL was fined.
Sorry to divert from the topic. Please tell us when you get the answer.