Sign an enterprise agreement that speaks to data retention and destruction requirements. Part of what you pay for is to shift the liability to the inference vendor.
These data retention contracts are black boxes; you never know how your IP was leaked, and it could end up in the model's training data. It's like trusting META with your privacy settings.
A contract satisfies our infosec program and cyber insurance requirements, confirmed by a corporate legal team. Our role is to manage enterprise risk and potential exposure within our risk appetite, not eliminate it.
(already minimizing sensitive data storage and transit whenever possible, as an entity operating in a regulated industry)