I have just disabled anonymous edits (i.e. coming from people without an account) as an emergency measure, since the automated Abuse Filter does not seem to work with Flow. Just today we had three spammers create threads in talk pages that would normally have been caught by the Filter. I will try to find a solution, but we will probably have to either get more people who can monitor recent changes and delete spam posts or keep editing to accounts only.
This wouldn't actually be a big change, since account creation is still open to anyone and most anonymous edits have always been spambots or trolls anyway. Let me know your thoughts!