This part of GDPR has always seemed completely unpracticable/unenforceable to me. How would a non-EU company even know that one of their customers is an EU resident and only temporarily visiting? Most services in the US aren't asking for my passport, at least.

Practically, I'd assume that this will be interpreted by courts to only apply to companies "intentionally doing business with/commercially targeting EU residents", which is already the case for similar scenarios (e.g. that's how, to my understanding, German law requiring all sites to provide an imprint has been interpreted by courts).

In any case, I suppose we'll have to wait for precedent; I'm not aware of any at the moment.