[lcnPylGDnU4H9OF]

I think this might be moot. "Everyone living in that household can use Netflix wherever they are — at home, on the go, on holiday ..."[0] suggests that they'll use some mechanism other than IP to determine that there is against-terms "password sharing" going on. Probably something like device sessions instead.

[0] https://about.netflix.com/en/news/update-on-sharing-may-us

[andromeduck]

Probably just cooking sniffing and some sort of grace period if you're not on the same network for a while.