I once flew in a 4 ship close formation of Pumas for a flypast during a "Freedom of the Town" ceremony.
When we returned to base, the aircraft next to me in the formation had about 400 metres of Terylene kite braid wrapped tightly around the tail rotor pitch change rods. The pitch rods had begun to bow inwards. There was no sign of either a kite or a small boy.
Another worrying episode was a large radio controlled aerobatic aircraft that shot right across the front of my aircraft, only a few yards in front, same height. I was crossing Northolt's main approach, at 1100 feet, well inside the Heathrow CTR, under radar control.