"It'd be impossible for Google Analytics to not collect data from a incognito tab without it knowing that it is incognito somehow (like if Chrome attached a header to all outgoing requests that said incognito=1 or something)."

Developer Tools allows users to block specific requests, e.g., to google-analytics.com, either by URL or by domain. It is possible (but not implemented by Google) to automatically activate such request blocking when an incognito tab is opened. This is one way to stop GA tracking when in incognito mode.

The quoted warning "Your activity might be visible to:" lists a few third parties, e.g., "websites you visit", "Your employer or school", "Your internet servive provider".

However it does not list Google, LLC or Alphabet, Inc. The complaint is against Google and Alphabet, not the other other third parties.

Here is a copy of the complaint:

https://www.classaction.org/media/brown-et-al-v-google-llc-e...

For those who will not read the complaint:

In addition to GA, the complaint alleges Google tracks users without consent via Google Ad Manager, the "Sign in with Google" button, including Google Approved Pixels, despite incognito mode or privacy settings.

It further alleges tracking without consent via Android, despite igcognito mode or privacy settings, as described in the following paper

Douglas C. Schmidt, Google Data Collection, DIGITAL CONTENT NEXT 1 (Aug. 15, 2018),
https://digitalcontentnext.org/blog/2018/08/21/google-data-c...

Finally, it alleges Google conducts tracking without consent, despite incognito mode or privacy settings, via the "X-client-data" header in Chrome (formerly "X-chrome-variations") as described in the article

Thomas Claburn, Is Chrome Really Secretly Stalking You Across Google Sites Using Per-Install ID Numbers? We Reveal the Truth, THE REGISTER (Feb. 5, 2020), https://www.theregister.co.uk/2020/02/05/google_chrome_id_nu...

The complaint argues Google is representing to users that "You are in control" via Google's incognito mode and privacy settings however Google is nonethless tracking users via all of the above methods without user consent. This arguably constitutes misrepresentation.

To recover damages, the wiretapping laws require that there must be some injury. If users' privacy is violated, what pecuniary loss do they suffer? This is usually why these lawsuits always fail.

This complaint uses this source to try to estimate damages

Tim Morey, What s Your Personal Data Worth?, DESIGN MIND (Jan. 18, 2011),
https://web.archive.org/web/20140703174004/http://designmind...

Contact info: $4.20/yr

Demographics info: $3.00/yr

Web browsing histories: $52.00/yr

The complaint also cites the "Google Screenwise Trends" program where Google pays users $3/week to be tracked.

The complaint mentions the websites Latome and Killi where users can voluntarily sell their personal data, noting that Google OTOH takes such personal data without asking for permission and without providing compensation.

The complaint also appears to suggest that the user's ability to obtain the maximum value from granting permission to collect and sell her personal data, e.g., via Latome or Killi, is decreased as a result of Google's unauthorised collection and sale of it without the user's consent.