It's time for a lawyer letter. See the Computer Fraud and Abuse Act prosecution guidelines.[1] In general, the US Justice Department will not consider any access to open servers that's not clearly an attack to be "unauthorized access". But, "However, when authorizers later expressly revoke authorization—for example, through unambiguous written cease and desist communications that defendants receive and understand—the…
Do we need a "robots must respect robots.txt" law?
(Disallowing * isn’t usually an option since it makes you disappear from search engines).