I have read about the video tape delay stories. When "Nightwatch" moved to Washington in 1984, with Charlie Rose, they had call-in shows. Harry Remmers figured out how to use an 8 second delay using two 1" tape machines. I think they were RCA machines. I have no idea if that was the first time it was done or not.
We did that on several Nightwatch shows. We had a marked stick, or board, to be sure the machines were the same distance apart every time. There were rollers to remove and a few other adjustments to make it work. It did work fine.