Heres a picture I've got of window cleaners using a wfp in 1960. So as you can see this is a very old idea, just show this to old cranks who think this is new fangled technology. We are doing nothing new so don't feel so worried about making the switch over, it's just with new technology that this technique has become a better solution over ladders.
here are early adaptable goosenecks from mr long arm
here is an early trade show in the 1970's, notice the the signs behind the men
I hope you enjoy my research, Luke