@julia mhmmmm ...
Optional thing required to enable email confirmation is required to login..
I think it may help to prevent fake email users.
Genuine email with verification only the option to access the forum then automatically they Register and verify the email.
Now they just typing random words followed by @gmail.com and automatically it logged in without verifying email..
If they put random email also it should not redirect to logged in state from Registration page.
Whether they again put that email, password it should not log in, and it should give an error email confirmation is required to login please click the verification link sent to your email.. something like that..