"3rd-party apps accessing these APIs must use the data to provide user-facing features and may not transfer or sell the data for other purposes such as targeting ads, market research, email campaign tracking, and other unrelated purposes. (Note: Gmail users’ email content is not used for ads personalization.)
As an example, consolidating data from a user’s email for their direct benefit, such as expense tracking, is a permitted use case. Consolidating the expense data for market research that benefits a third party is not permitted.
We have also clarified that human review of email data must be strictly limited." [0]
[0] https://cloud.google.com/blog/products/g-suite/elevating-use...
As long as the [I agree] section says "We send all your email to market researchers for money", then it's fair game to publish.
Maybe not. Probably not. But I sure know I don't want to lose any freedom. Can this be mitigated with custom-generated API keys?