I’d assume it has exactly the consequences you think it does, but I don’t know that and it becomes more of an unknown as more third parties are layered between you and the LLM.

I’d assume the right prompt by another user of the same underlying LLM on another platform could well expose your private information / content / passwords and would treat this with a lot of caution until you get satisfactory evidence otherwise.

Yes however langchain is not finetuning, it's basically indexing!