[MM3-users] Recaptcha for subscription requests?

Hello Mailman3 users,

I've seen a massive uptick in bogus subscription requests with real addresses, either being used to DDoS outside mailboxes or just for intrusion/scanning. (It looks like a lot of fake random strings for name and then valid addresses like scanning/scamming tools like Acunetix generate.)

When these hit thousands of gmail addresses they get classified as spam and hurt our overall deliverability.

Has anyone yet built a CAPTCHA integration for the Subscription/Sign Up path?

Regards, --Jered