I thought if you turn off App Activity then that's good enough to protect your data?

Nope, not if you are in the US https://ai.google.dev/gemini-api/terms#data-use-unpaid

> To have persons read them and decide how to use them for training.

Not that I have any actual insight. but doesn't it seem more likely that it will not be a human, but a model? Models training models.

> To help with quality and improve our products, human reviewers may read, annotate, and process your API input and output. Google takes steps to protect your privacy as part of this process. This includes disconnecting this data from your Google Account, API key, and Cloud project before reviewers see or annotate it. Do not submit sensitive, confidential, or personal information to the Unpaid Services.

Unless you have the enterprise sub of openAI theyre training on your data too