The Flight Engineer on one of these airshow trips (when they were allowed) was telling me that on the way there, the Training Captain did a full waggle and control reversal of the controls to practice the manoeuvre. After enormous gyrations of the sky, they checked and they'd lost 50 feet altitude. So at the airshow, they're steaming up the runway at 50 feet with Flight Engineer thinking 'what an impressive sight we must be' and then he said '***** me! He went and did it again at 50 feet!' A serious loss of sense of humour occured!
We didn't do many airshows like this before display flying was banned for non specifically trained display pilots. Too many people overdo it in the excitement.