I assume that they'll treat an empty, or obviously fake account the same as they'd treat you not telling them your account name in the first place.
Which is to say, they probably won't do anything in most cases, they'll just tick the "enhanced security" box so that someone else has to lay their hands on you.
This is a government bureaucracy, they're not out to get you, they're out to get their pension whilst covering their own arse.
Biting the hand that feeds IT
