For example, if you're locked to the US region and watch something that is only available in the US while visiting, say, the UK — would that break any of Netflix's license agreements?
Distributors don't care about this, they care about geographically determined licenses. And apparently they want to see that this is technically enforced to some degree.
Try to buy some apps in one country and download them again while in another.
Last time I read about this it wasn't possible to do so.
This was the issue I read about, just the example was from a guy in Europe that moved back to Canada.
"Tough"
They'll never do this based on billing address because they don't care where you're FROM, they care where you ARE.
If they did that all it'd is have one of our mates living in the US to make us an account and we'd never have to VPN again.