While there are good specific reasons for clients to register when a user has logged in, it should not be seen as a proxy for a tracking consent signal.
One can login to a site and still not expect to be tracked, while on some sites wish to be tracked without having to login.
A user can register tracking consent, after being validly informed of the specific ways and purposes they would be tracked on a particular site, by clicking on a browser chrome UI element, or perhaps from a permissions API request (properly frequency limited by the browser). In Europe this is not only legally required but it becoming a well understood facility on many sites.
There still needs to be a browser mediated tracking consent signal, to be considered by browsers independently from the isLoggedIn signal.
While there are good specific reasons for clients to register when a user has logged in, it should not be seen as a proxy for a tracking consent signal.
One can login to a site and still not expect to be tracked, while on some sites wish to be tracked without having to login.
A user can register tracking consent, after being validly informed of the specific ways and purposes they would be tracked on a particular site, by clicking on a browser chrome UI element, or perhaps from a permissions API request (properly frequency limited by the browser). In Europe this is not only legally required but it becoming a well understood facility on many sites.
There still needs to be a browser mediated tracking consent signal, to be considered by browsers independently from the isLoggedIn signal.