At that time, there were no “videos” on every cell phone, nor the attitude of recording on them for publication..
Hand-held film cameras? Some. But being recorded on film wasn’t “cool” nor trendy for teens - that was something their parents and grandparents did on holidays.
The richer neighborhoods around DC would be near certain to even have a few Beta-VHS cameras at the time. (The VHS/Beta wars ramped up after 1975.)
I suspect that the poster was referring to one of her current students.
I can’t imagine she lectures in that little 13 year old fake voice.
Oh really?
So no one has recorded her lectures in , oh I don’t know....the last two years?