I remember Jonh Lee Hooker came out w/this thing called "The Healer" or some stupid thing, & Warren was all like this guy is nuts cuz he'd stay on that E chord for however long he'd like. Some nights he might stay on it for 5 bars before he changed, but if you got to stick around, you had to change when he wanted to, & if you couldn't do that, you didn't just get fired, you got that look!

They played together a lot, or at least several times.  The Fillmore is across the street from JL old club, the Boom Boom Room.  So anything is possible.