Something I've recently discovered is that if you use Gemini with a Google Workspace account, it shows you a disclaimer that your chat is confidential, will not be used to train the model, and cannot be reviewed by a human. I was never shown this message with a regular Gemini Pro account, so I think it's safe to assume on a normal user account it is not confidential, will be used to train the model, and can be reviewed by a human.

I'm not saying you should trust them regardless, but if you must use Gemini for some reason, the workspace plan with Gemini Pro is $3 cheaper and allegedly has more privacy protections since it's targeted towards businesses. Just figured I'd share my findings!