1973 - Alex Harvey
Canned Heat, Nazareth, Edgar Broughton Band, Groundhogs, Sensational Alex Harvey Band, Medicine Head, all appeared at Buxton Festival in Derbyshire, England. Hell's Angels arrived in force and proceeded to drink the site dry. Initially they paid for the booze, but when the money ran out a deputation was sent into the audience to collect donations of 10p per person. About 20 minutes into his set
Chuck Berry was showing one of the Angels how to do his duck-walk properly. He did one from one end of the stage to the other and disappeared into the wings. The band played on, the Angels bopped, and Chuck legged it to his car and drove off at high speed, never to return.
I wonder if this is what the band was playing as he hauled ass.