As I just found out, there's a difference between quarantine and managed isolation. (I'd often used quarantine when I should have used managed isolation.
Quarantine is for people with symptoms, or a positive test, and you're not allowed to leave your room. Managed isolation is for people arriving from overseas without symptoms, and allows you to go out for a (contact-free) walk, and makes you eligible for exemptions.
So these women were in managed isolation, despite one of them having symptoms.
Interesting also, that what Landau, the Avatar producer, described (not allowed to leave his room) was quarantine, whereas the Avatar crew should have been in managed isolation (being symptom-free), which was what other people have described.
Makes sense. maybe that covers the mingling thats often mentioned here, you can mingle in managed isolation, just as we did at New World in Level 4. Social distancing. Good headline though