Congratulations. You're an edge case.

In my experience there's enough slack in practice for these edge cases. At least in CA, it's very strange for a cop to cite a tourist because their car is not road legal in CA but is road legal in their home state. I've known many people who just get off with warnings, sometimes years after they've actually moved to CA (and just never bothered re-registering their car their, even though that's technically legally required). Ofc YMMV