The problem is Gents, many of the 'flags of convenience' (sorry, ICAO contracting states), have no idea how their fleet is being operated in Europe. Some don't care a hoot. Maybe the FAA is the best of the bunch, but many of the others do not give a damn if you dump your aircraft on my house.
A recent example - "Under CAA rules, the pilot would have been required to undertake a course of training and tests to obtain a type rating on the Nomad aircraft, whereas FAA rules make no such provision."
Air Accidents Investigation: GAF Nomad, N5190Y
Impressive! How come an aircraft, overseen by a near perfect "service orientated agency (FAA)" be allowed to fly in the UK under such conditions? Simply - out of sight, out of mind. It wasn't any Americans that were going to die that day.
Everyone is entitled to 'the pursuit of happiness', but let's do it safely under proper oversight by a local Authority = the Authority where the operation is based. If you want to "go around the laws", do it away from us innocent bystanders.
By the way, how many G registered aircraft have crashed in the USA? None, ever. Why? because the Feds don't allow you to own and operate a foreign aircraft there. N reg only. What's good for the goose, will soon be what's good for the gander!