@darius hope to see this trail of thought continue into real experimentation!
It feels like there would be a whole lot more common ground between the preemptive defederators and the wait-and-see crowd if dubious instances could be quarantined away whilst still having the option to poke holes for individually trusted users.
We also need more documentation on the connectivity options available to instance admins:
https://writing.exchange/@erlend/110671771287690551