I know Kitbag's problem. Some years ago my insurance company declined to offer me insurance because of my profession. These clowns believed that I might possibly bump into a large aircraft and lumber them with an unpleasant claim. But you can not argue with idiots like this, even with fact. Unfortunately, airports use legislation like the Aviation and Maritime Security Act to give themselves undeserved powers to chase down errant motorists who try to avoid greedy parking charges - this leads half-witted underwriters into believing 'airside' is wherever this act applies. My advice would be to change your insurance company.