David told us about this concert, here is a link to the Wikipedia entry.
https://en.wikipedia.org/wiki/In_the_Flesh_(1977_Pink_Floyd_%27Animals%27_tour)
The Montreal show, 6 July 1977, the final performance of the tour, ended with Pink Floyd performing a blues jam as the roadies dismantled the instruments in front of the insatiable audience who refused to let the band leave the stadium. A small riot at the front of the stage followed the band's eventual exit. Earlier that night, Waters spat in the face of a disruptive fan;[3] The Wall grew out of Waters' thoughts about this incident, particularly his growing awareness that stardom had alienated him from his audience.[4]
Cheers
John