This will challenge you viewpoint and polarize opinions from Incredible Expert to Incredible Idiot. Either way don't do it at home - you'll get in a lot of trouble.
Very impressive flying and he's not doing anything wrong under US law AFAIK.
Though of course that would be illegal in Oz due to FPV flying being illegal*. Of course lots of people still do it here anyway and, for the most part, do it safely.
* unless he's a commercial operator with the appropriate exemptions and licenses.
You reckon a few people have been doing similar stuff? you notice that the reaction of the driver of the train was immediately to close his window, reckon people have tried to fly through the cabin?
I couldn't resist, sorry
that is insane stuff. 
