I once got reprimanded for not wearing one as I clambered out after a cross-channel trip. The gross stupidity of this was that I was wearing a bright orange survival suit plus a life jacket with high vis reflective tape. It didn't stop the barking mad jobsworth from taking a pop though.
Kemble will be fun, as I'm planning to fly in to the PFA Rally by paramotor, weather willing. I'm looking forward to seeing the high-vis jacket Gestapo determine when I'm "in" my aircraft or "out" of it before they pounce. Anyway, there's no way to put on a high-vis jacket before "removing" this type of aircraft from one's back, so the idiotic safety police will just have to do their worst.
VP