You're assuming I can't hop on the phone (appearing to come from a known number using Caller ID spoofing, using LinkedIn to get a general idea of the org chart) and bluff my way through it with your underpaid, overworked help desk staff. People are the weakest link.
This is only a few steps above Indian scammers taking remote control of users’ computers and convincing those users to send them hundreds of dollars of gift cards to prevent legal action by the IRS. Consider your average user, not the HN participant.
https://www.youtube.com/watch?v=YVqurfWzB-Q (Hacking Humans : Social Engineering Techniques and How to Protect Against Them - Stephen Haunts)