Participated in a similar event at the RAF Buchan families day in 1986 when, en-route back to ABZ from some rig or other we were asked by Aberdeen Approach if we could do a flyby for them at the CO's request. My Capt had displayed the Chinook before and agreed readily.
I had to call knock it off as we came to a quickstop v. high hover and the dunnies went over and away all in a row, followed by the ice-cream van's awning, hats, clothing, rugs and entire picnics followed in a blizzard of dust and debris. I swear I saw daylight under Mr Whippy's tyres...
The ensuing call from the CO as we were slinking out of the Ops room half an hour later was, astonishingly, not a furious b@llocking but effusive praise and thanks. We had to wonder if he had actually attended the event!