Sure... it's intelligent enough to gather that info, but pursuing it to the point where they want to cut you off is another thing. The only retaliation they have is to cut you off(that I can see -they aren't spending thousands to take you to court for $20/mo) and does that hurt the user or the business? Their only form of resolution literally takes money out of their own pocket!
I'm just speaking to your comment, from their intent it's to prompt you to verify the household if it notices activity. It
is tracking you and has been tracking you for years which you denoted you didn't think it did.
From a Forbes article in Feb 2023: "Netflix will have ways of knowing if you are still sharing your account with someone outside of your household. That’s because the streaming service collects a lot of data about you, including what you watch, where you watch it, the location of your home, and device IDs. This information can be used to ascertain whether it’s you watching or someone in another household.
In countries where the password sharing crackdown is active, Netflix is tracking who shares their accounts via the devices used to connect to the platform. It will enforce the end of password sharing by asking devices to “check in” periodically in your home location around once a month. If you have kids at college, they could check their devices in when they are home, if they can get back every 31 days.
Netflix describes in its shareholder letter how you will still be able to use your devices outside of your home once the crackdown begins. “As we roll out paid sharing, members in many countries will also have the option to pay extra if they want to share Netflix with people they don’t live with,” the letter reads. “As is the case today, all members will be able to watch while traveling, whether on a TV or mobile device."
When Netflix detects that someone outside of the household is sharing the password, it will block the device and give them the option to add their own account."
You can expect a similar enough process in the U.S. Whether they give an adjustment period where they are not enforcing it but rather giving reminders instead IDK. But this is a slow world-wide thing they seem to be taken on. The U.S. isn't the first country they are doing this with either. Latin America was first last year and in Feb of this year they rolled it out to Canada, New Zealand, Portugal and Spain. It will be rolled out (according to Netflix) in the UK as well.