Someone please confirm my idea (or remedy my ignorance) about this rule of thumb: Don't train a model on sensitive info, if there will ever be a need for authZ

Someone please confirm my idea (or remedy my ignorance) about this rule of thumb: Don't train a model on sensitive info, if there will ever be a need for authZ more granular than implied by access to that model. IOW, given a user's ability to interact w/ a model, assume that everything it was trained on is visible to that user.