If I was at a model meet at Old Warden, or anywhere else, and a "jobsworth" started asking to see people's BMFA insurance, while refusing to identify himself, I would tell him in no uncertain terms, to go forth and multiply!
How did this man stop people flying?
Its also occured to me that this person could well be the same one who Shuttleworth are looking for......Unless the man concerned is prepared to step forward and identify himself, and his connection with Old Warden!(or the BMFA!)