This seems like it is nonsense. Recording was well understood to exist by the general public in the US by this point. Not everyone had a cassette recorder, but plenty of people understood that recordings could be made of audio.
Also, recording and eavesdropping was associated with rogue phone company employees. We don’t have strong wiretapping laws because of the foresight of congress. Phone company workers were crooked as hell.
Plus, the fact that any non-government person could surreptitiously record a conversation, and that recording be useable in court, didn't substantially change until this century, and even today it's mostly a mishmash of state laws preventing such disclosures, those laws are inconsistent, and in some states there's still effectively little preventing that from occurring. And the ability of the government to leverage third-parties to get around 4th Amendment precedent is still in flux.
All-in-all, I would think the ability, and knowledge of the ability, to record a phone call was entirely irrelevant and uninteresting in the 1940s, at least regarding people's expectations of privacy. But I'm curious if there's evidence to the contrary.
At the time, AT&T’s marketing was all about trust, a mission ethos to serve humanity, etc. They also had a close relationship with government at all levels. Their goal was to avoid awkward questions.
Yes and no. They understood that recordings could be made of audio, but they expected everything to be live and ephemeral.
That's why if you listen to old radio shows, very often the introduction includes the phrase "...coming to you by transcription from {$city}..."
"Transcription" is what they used to call recording, and people were almost always told that what they were listening to was not a live broadcast.
It's so common, I have to wonder if there was a period in time when it was a legal requirement.
https://www.smithsonianmag.com/innovation/spread-answering-m...