It's a bad place to go filming if they don't want disturbance by aircraft.
Indeed. But it is only a REQUEST. Safety of flight in this Class G airspace is entirely up to the pilot so if you're there VFR with a cloudbase of 2100ft you are unlikely to be able to comply if for some reason you are unable to go 2nm south. So you then do your best, which might be crossing at 1900ft. I don't expect an overflight at 1900ft has much difference noise-wise to one at 2201ft. As I said they're only asking you to be nice. If being nice would result in your or someone else's death I suspect they might forgive you not complying.
NS