The framing of Gemini as a guest who 'leaves the room' is doing a lot of heavy lifting. The room is Google's server. The guest works for Google. At best you're trusting a company whose entire business model is knowing everything about you to voluntarily not look.

My domain hosted at google workspace mailing lists are increasingly marked as spam, because google uses central Google identities sending them and every workspace @mydomain is tainted by whatever spam other hosted workspaces acquire. They haven't worked out how to dkim/spf them into buckets which other big mail players won't cast as bad"

The value proposition behind google hosted domains is falling.

> whether or not Gemini really does forget what it has seen as easily as claimed

Whoever is writing this seems to have absolutely no clue how AI works.

Given that Google is clear about the fact that they don't train on your emails, the worst that could be happening here is that... within the scope of your account they maintain an extra index or two, or... additional synthesized data, in addition to the many indexes that they already maintain over your email.