Then I must have misunderstood. In this particular case I though the Yubikey documentation didn’t mention how do to things for the particular case of having a usb-keyboard setup.
Haha 
Fair enough! But it’s still great to have accurate documentation so that we can simply point the users to, in case they haven’t checked before.
Regardless, I still stand behind that comment. In an ideal situation the software tries to understand what the user is attempting to do and helps them (discourse does that to a fantastic extent).