I would think the law is more concerned that the UK version of the service, is being paid for by a UK account registered at a UK address, and paying UK fees. It's still being distributed to the UK as far as every financial transaction is concerned.

But I see your point, it's a license issue. I guess Netflix's lawyers should sharpen their pencils, because what you described is already happening, because despite their best efforts, the VPN's have managed to remain ahead.