You only need 100 hours and an aircraft capable of 100 mph to enter, if more people showed an interest perhaps it wouldn't be the same crowd of pilots every year.
I agree that they take over an airfield without a though to other visiting pilots, but they are zooming around at full power reasonably close to the other competitors, and the airfield is usually a main turning point and the fnish line.
I've watched a few races and the handicapping has never come even close to working, Strange in these days when it's all tracked with GPS and the exact speed of the aircraft is known, someone needs to buy the guy a calculator!
I think interest has dropped a fair bit since the fatal crash at bembridge a few years ago.