That's the point OP was making. They would know that you know that they know. This means they could be very, very targeted with an email/social phishing attac

That's the point OP was making. They would know that you know that they know. This means they could be very, very targeted with an email/social phishing attack to try and get a newer password or other account information by referencing the previously compromised site. It could help the bad guys establish trust. A bit tinfoily but well within the realm of possibilities if the lookups on this site are logged.