That's not sufficient. If a user copies customer data into a public google sheet, I can reprimand and otherwise restrict the user. An LLM cannot be held accountable, and cannot learn from mistakes.
Don't use AI/LLMs that have unfettered access to everything?
Feels like the question is "How do I prevent unauthenticated and anonymous users to use my endpoint that doesn't have any authentication and is on the public internet?", which is the wrong question.