Given that situation and GitLab.com's experience, I wasn't going to submit myself to a maintenance burden like that. However, now that we have 2FA and we can require accounts to be blocked until they set up 2FA, I'm thinking that's an additional barrier on entry, which I hope is enough to keep spammers out.

 

Are you going to require 2FA for existing accounts as well?  And what 2FA methods will you support?  SMS?  Google Authenticator app?  Security (FIDO) keys?  (I'm finally going to set up 2FA for my personal accounts using security keys, so this comes at a good time. I've had to add 2FA to my github account already, using the authenticator app.)

I've actually been using my FIDO key successfully to log into the admin account for the last half year or so. While I can't force people to shell out for a Yubi key v4 or v5, I'd love for people to get a U2F key at the bare minimum. It used to be supported only by Chrome, but FireFox has U2F support now too. (And my experience over the past 6 months has been with FireFox exclusively.)

U2F keys exist at reasonable prices of less than 10$.