Google sued for data-mining students' email 12 years ago
The suit maintains that, because such non-Gmail users who send emails to Gmail users never signed on to Google's terms of services, they can never have given, in Google's terms, "implied consent" to scan their email.
This. One victim is the private mailing list: There's always at least one sap who subscribes using google mail.
My personal hope is that suits like this will one day push them to discontinue gmail.