Rick Weaver, the WIOD play by play guy, always took credit for the hanky waving tradition. And trust me, he would be furious when he didn't spot enough of them in action. Radios tuned to the game were all over the Orange Bowl in that era. Weaver's voice turned noticeably disgusted when he thought the fans were either deflated or too complacent to wave the white hankies during a key stretch of the game. Normally it was a celebratory move.
I was 13 years old in 1972, very tall for my age but still looking up at the forest of white hankies in everyone's outstretched hand. I remember trying to peek between the hankies when Miami had scored, the fight song was suddenly blaring, and I was straining to watch the players return to the sideline and be greeted by Shula and other coaches/players.
BTW, one of the few bright spots of last Sunday's game was both teams in white pants. Dark pants could not be more sloppy in the NFL.