Forum OpenACS Q&A: Re: Groups -- the public, unregistered users, permissions
For some reason forums does not redirect to login right when you attempt to post. Perhaps that is to encourage registration. That is, if you have already typed your message maybe you are more inclined to create an account than if you are presented with the registration screen before typing your message.
If not allowing annonymous posting what would you expect the behavior to be?
I suspect we should always tell the user the consequences of aborting the registration process.