Too much discussion about the Holy Roman Empire over dinner? People talk to get things of their mind sometimes, not the infinite pursuit of conversation.
If you don't want your family to know something, you shouldn't tell it to OpenAI either.
Yeah, I think this is an over reduction of personal privacy models, but can you tell me why you believe this?
Your family is in a a position of power, which is why it can be scary to share information with them. People at OpenAI are also at a position of power, but people who use their services seem to forget that, since they're talking to them through a computer that automatically responds.
tldr: power (or if you want, impact) is the linear dimension, likelihood adds a second dimension to the plane of trust.
For example, one's spouse typically has a lot of power, but hopefully a low likelihood in practice.