It looks like YouTube is following the same path as Netflix did earlier by cracking down on sharing family subscriptions outside of one household.

A few key points from the news:

• 📢 Notifications and restrictions: Some users are now receiving a message from Google. Their account still exists, but they lose the YouTube Premium benefits such as ad-free viewing and background play.
• 🌍 Still small-scale: So far, reports have only come from some countries.
• 🏠 Household verification: Users can contact Google to prove they do live in the same household in order to regain their Premium benefits.
• ❓ Unclear enforcement: It’s still not clear how Google is technically or practically verifying whether people live in the same household.

So this seems to be a test phase or gradual rollout, where YouTube is checking how strictly they can enforce the Family plan rules.