Is it possible to make the "display name" field on the registration screen vanish and/or auto-populate with the same value as the login name field?

(Goes to poke around in the code, just in case...)

Curiosity strikes me to ask why you'd want this...

Think of this, it's a security feature, and a preferance field all in one...
1. Someone can have one login with a differant PDN.
2. Someone can have the login as "gizmo" and the display as "Gizmo" (or GiZmO should it strike their fancy)

I understand why it's there, and think it is a great idea, but not all of my users do. 99% of them use the same name for both, so I'd like to make it optional on the registration screen/default to their login name... it just saves me getting questions about it and confusing my users.

I use to do this on the older versions (as well as the password field so the password comes in their new user email.)

Cant seem to remove them this time. Been searching for how but cant see any info on it now.

please?