Tell me how does it matter. Netflix gets 800 and 4 people are watching simultaneously. Some people have better bonds with friends than they have with their families.
Even sharing within my family would mean usage in 3 different cities/places. So what would be the advantage/disadvantage for Netflix to enforce such an illogical, absurd rule. No company does that. I am even sharing my Zomato Gold membership with a couple of friends.
Do you do that with your phone plan? There are family sharing options there as well.
It's there in their T&C for legal purposes. Someone tomorrow hacks their servers/copies and uploads one of their shows to torrents or something then the account holder will be held responsible.