alt Hacker NewsTwitter has IP addresses at the very least. HBO will then subpoena the account's ISP. If the account had the checkmark pro plan or whatever it's called, it may have or be able to obtain legal name and address for payment details, or its payment processor (Stripe I think) would.
And all of this falls apart if you use Mullvad, who will be happy to fax HBO lawyers a blank sheet of paper.