All such requests have the same issue: disruptive users will ignore administrators and other users who inform them of their mistakes; it will get even harder for them to improve and they may be blocked without having (actually) received a warning.

This may be less important if we think it's ok to make it easier for users to damage themselves (i.e. to give them a feature which they'll abuse, and where abuse will naturally be punished by wasted time, diminished personal development and eventually block).

@Nemo_bis — You're absolutely correct — there is an underlying question to all of these user-to-user mute/blocking tools of collaboration vs. individual control and safety. This question will be forefront in our minds as we conduct community consultations with various Wikimedia communities to come to an understanding if these features will help or help individual users and the communities as a whole.

If these features proceed to development, it will be our responsibility to design them in a way so users who opt-into them understand the potential consequences if used carelessly.

I think this task should be marked as Resolved (in as much as the feature is deployed). The "blocking" sub-tasks clearly don't block it. We don't use "tracking tickets" in Phabricator.