Ah yes, car alarms... I remember attending a Friday 'press day' prior to the Barton show. I was standing by a Sea King which was parked and shut down just the other side of the fence from the car park, when a Harrier, low and fast approached the field from the north. "Just aim for the Sea King", said the controller. The Harrier streaked in at about 20 feet AGL and and only just subsonic (it was silent as it approached, growing rapidly from a spec to an aeroplane).
It flashed over the Sea King in an tremendous crescendo of sound - the helicopter's rotor blades flexed considerabley in the slipstream as it flashed a few feet directly over its mast head at about mach 0.98. And all the car alarms in the car park went off.
I loved press days. Even the more lax airshow rules back then didn't apply on press days.
SSD