Netflix has profiles intended to keep track of different members of the households preferred shows. The most expensive plan only allows 4 screens to be used at one time and they might notice when the "family" members appear to be in different countries.

In theory a single someone can share with another single someone but multiple households would be hard pressed to do so as it would be easy to exceed the number of screens preventing others who pay for the service from watching.

If you aren't already paying the extra $5 for 4 screens and UHD you only get 2 HD screens which is even more unsuited for sharing.