Not the guy you responded to, but I would assume ”they keep it safe” somewhere in a cold storage. Just in case they decide to train on it in a later phase.
I don't think they'd really be willing to risk the whole company on a small subset of prompts. It's not "keeping it safe", it's retaining proof of illegal activities.
Small subset of prompts? You mean literally every Kreti and Pleti who lets Claude go through their entire codebase is considered ”small subset of prompts”?
There is no evidence for these types of claims. They likely need to retain data for legal purposes (I think all of them are under injunctions from court cases), but there’s no way they will be breaching contracts with all these enterprises just for a little bit of data. Those contracts are their lifeline.