Not to shame the author--I'm glad when people share the stories--but the thing that surprised me is that the author knew the "hang up and call the number on you

Not to shame the author--I'm glad when people share the stories--but the thing that surprised me is that the author knew the "hang up and call the number on your card" advice but didn't seem to understand why it's common advice. The whole point is precisely that caller ID is completely unreliable. If caller ID were secure and authenticated the caller, there'd be no need to hang up.