I think it was never clear if residents of EU included people with citizenships but are currently located outside. So it would be safest to honour all requests rather than risk it.
even if you live outside of your country, you typically still are considered a resident of the country of citizenship, because to declare you a non-resident someone would have to prove that you aren't still registed as resident or don't don't have a home there any more and are not going to go back any time soon, which you could do any day.
There are complex laws governing residency which vary country-by-country. It's not atypical that, for example, if you spend 183 days in a year somewhere else, you're no longer a resident.
You're generally only a resident in one country. This governs taxation -- taxes are primarily based on residency, with some caveats. As a US citizen living in the EU, you will not pay the same US taxes as you would if you were living in the US, and in many cases, zero taxes.
to change your status of residency, proof would be required.
and it depends who is asking. maybe i don't pay taxes as a resident, but for visa purposes i may still count as resident in my home country.
this is relevant now as china allows people only to enter by direct flight from their home country or country of residence. this is really messing with people who have their family in a third country. they have to make a detour to their home country if they don't have a residency visa for their family's country.
also if i go travelling for a year, i don't loose my residency status unless i stay somewhere long enough to establish residency there. that is, if i have a visa that allows that.
Proof is not required. In the US, for example, you file taxes on an honor system.
If you've lied, there are periodic audits, and you might get thrown in prison.
I assume you can lie going to China. If you do and get caught, you'll probably never be welcome to visit China again (or fines, or prison, or some other consequence; but most countries would just keep you out).
GDPR is very clear -- EU citizens living outside the EU are NOT covered. US citizens living in EU are covered. That's not uncommon for laws; I don't get a ticket for breaking US traffic laws in the EU, or vice-versa. Very few laws reach across borders like that (taxes, some forms of child abuse, some forms of bribery, child support, arms trafficking, some types of military service, espionage, etc.).
However, as the other poster pointed out, from the perspective of a tech vendor, understanding the difference between:
- EU resident
- EU resident using a VPN in the US
- EU resident traveling in the US
- EU non-resident living in the US
For each request which comes in is practically intractable.
GDPR is also framed as a basic, universal human rights law. That also can have unintended tentacles. If you don't want a liability hole, it makes sense to honor GDPR for everyone, in practice (even if not under your ToS).
Practically, that's what everyone does. I've never had a GDPR request declined on the basis of residency (the last qualification being important).
That said, I've never had a problem using it from the US.