To clarify it further, for the case I described, I did not assume a user that actively tries to suppress the signal to Google, but assumed a user that only does

To clarify it further, for the case I described, I did not assume a user that actively tries to suppress the signal to Google, but assumed a user that only does not visit Google search (or any other its services). I then assumed that at certain moment this user can be uniquely identified (by AdSense, Analytics etc). Then accesses to pages without active tracking but with links to Google fonts or other passive API can be still identified with high confidence given the access happens from the same network. I do not know if such extra signal is interesting for Google, but it can be acquired. Also mind you that using an ad blocker is also a signal and can be assumed from the access pattern. The same logic applies also to an user who uses ad blocking but still uses limited Google services. Again I do not know how much Google finds this kind of signal interesting but it is possible to collect it.