I think GP has the following in mind:
- user has an account on GOOD.COM
- user has saved her password in her browser
- user navigates to BAD.COM
In this case autofilled passwords are safe and convenient since they alarm the user that she isn't at GOOD.COM.
A clickable link sent in email mostly works too, it ensures that the user arrives at GOOD.COM. (If BAD sends an email too, then there is a race condition, but it is very visible to the user.)
Pin code sent in email is not very good when the user tries to log in to BAD.COM.