Do you happen to remember the phone number that the call originated from? If it's a phone number that's published on Vanguard's site, at least one could add tha

Do you happen to remember the phone number that the call originated from? If it's a phone number that's published on Vanguard's site, at least one could add that phone number to their address book so that your phone says "Vanguard" when receiving the incoming call. That would offer some protection from phishing attacks in this case. (But you're right that this still trains people to be vulnerable to phishing attacks.)