[Typo3] Comments only for registered users

[Francesco di Francia]

I searched the TER. Then i looked into some typo3 sites to view the 2 
main comments extension in action.
I found that there's not a check that allow comment only BY registered 
users.
OK, i know that by the backend i can set the permission about the 
comment plugin. So in this manner only _A_ registered user can insert a 
comment. But, once logged, a user can fill the USER and NAME field with 
USERNAME and NAME of another registered users. I.e. USer A logs in and 
posts a comment signing it as User B.
There's a way to avoid this ? I'd wish that once logged, USER A can sign 
his comment only as USER A.