Asking the clerk to verify the photo ID in place of a Facebook account was a bit strange.
You'd probably have an inkling that their authentication is based on Facebook, so the photo ID thing is highly unlikely to work. (It seemed to be said more to counter the clerk's statement of not being able to validate users than a proposal of a real solution).
The clerk actually provided a real, practical solution (fake account) that the author does not seem to think very highly of.
