The BS forums prove that flaming still happens even when you require registration.

2 months of proof is enough.

So the flaming will not stop because of blocking non registered users.

You may lose some important information because of this, such as users that don't want their employer to know that they exposed something bad for Gnutella or things people may want to say because they are a developer and want to save "face".

You could for instance, pass any anon posts through a flame test, where it takes the vote of 20 different "registered" users before the post will appear.