Well, I for one would be more than a little concerned sharing the sky (and the road on the way to the airfield) with some-one who cannot see an object the size of a human on the ground in front of him.
The next question, in accidents where humans/aircraft have tried to share the same space time continuum, did the 'plane hit the human, or did the dozy human walk into the aircraft? A hi-vis vest will of course prevent this.
Edited to add:- Not much sign of them here at the moment
http://www.kemblecam.co.uk/