I've found this to be the case as well, on some occasions. Though usually what results for me is a weird work in which the reader's words get collaged with my own: that was the case with my poem on Robert Creeley, which I posted here recently.
But I never saw the listener-scribbling-in-a-notebook phenomenon more evident than at Silliman's reading in July '03 at 21 Grand in Oakland. At one point I recall looking down my row and seeing nearly everyone in it with their head bent over a notepad.
To be fair, there was some element of journalistic competition going on: nearly all the notetakers were bloggers who raced home to file reading reports. But I was curious to look back and see what it was I'd written down. So here, more or less verbatim, is what I wrote in my notebook that night:
VOG--Voice of God He looks just like his web site
Language Poetry an exercise in nostalgia-->SF poems
The ease w/which a spouse strips naked
why men don't put the seat up
aftertaste of honey mustard pretzel lingers in my beard
Planet of the Apps
In Philly a sleeveless shirt is called a wife-beater
This is CNN
Pubic hair caught between 2 teeth
World in which Strom Thurmond outlives Kathy Acker
Ovid among the Scythians
I woke with a tenderness above the cheekbone
Poet be like cod--looking at KK
Who listens? Who hears?
Silence of the looms
How will I know when I don't make a mistake?
finite words in a life--one hoards them
the joy of doubt