For the context of a prototypical nuclear family unit it all seems pretty straightforward, but once you introduce extended families, blended families, nannies, or abusive parents or partners you suddenly get a lot of complications and a level of granularity with permissions that would get pretty intricate.

For the CarPlay use case at least some kind of ad hoc “party” entity that all the devices flow into might be interesting. I’m thinking about how with the original StarCraft game one disc had a license for up to 8 instances of the game to play via LAN so you could have a single license key allow a whole LAN party. Some system like that where the auth flows through a “primary” account but everyone in the “party” contributes their own entitlements to it and can provide input.

My CarPlay with Apple Music shows a QR-code so others may add to the car's playlist. Never used it, coz why wouldn't you trust friends to just open the Music app and add something, coz they rarely have iPhones anyway

> For the CarPlay use case at least some kind of ad hoc “party” entity that all the devices flow into might be interesting

This feels like an under-explored space. I want to allow my guests to use <tech thing> for a period of time; I don't want to have to worry about permanent breakages or security issues. What can I delegate and how?

Yep i bet they don’t want to allow these policies because of screwed up and dysfunctional “families” they would suddenly be on the hook to support

Nexus Q was announced in 2012 (never shippe, and part of the launch emphasized it as a social shared-device. https://youtu.be/7NEXol4he2I#t=1h3m10s