From a legal standpoint, it doesn't really make all that much
difference if you were a logged in user or not. Sure, maybe you've
signed up for an account, but that doesn't mean you are who you claim to
be, and it certainly doesn't mean that the text you submit is owned by
you. Even if Wikipedia confirms your email address, it's going to take
an awful lot of work to track that email address down to a real person.
What matters is 1) can you show enough evidence to convince a court that
you created that text and 2) can Wikipedia show enough evidence that the
copyright holder allowed them to use the text under some sort of
license. And none of that even matters as long as Wikipedia is online,
because they are protected by the DMCA safe harbors.
At least if you're logged in and have confirmed an email address
Wikipedia might have a slightly easier time tracking you down to verify
who you are for real. But in essence you're already anonymous.