[est31]

How sure are they that it's one individual person that they are tracking? If you and others use the same computer, then maybe stuff might get mixed up. If "accessing" marketing categories includes read-access then your situation is worse than before.

What about the legal risk for Google if you opted out of the tracking a month ago but now google thinks you are a different person and is tracking you?

[giancarlostoro]

There's subtle ways to fingerprint someone, even how they move their mouse:

https://motherboard.vice.com/en_us/article/78k8pz/how-you-mo...

[Sir_Substance]

These are indeed tricky problems to solve.

They're also googles problems to solve, not societies. We're not required to provide solutions for them.

If google can't solve them, maybe that means google's business model is illegal.