What I don't understand with the "wait and see" people is the presupposition that it means to federate day 1 and see if they fuck things up to decide if defederation is needed. Their reasoning often includes "two clicks" as if the amount of effort defederation takes was the concern people had.
"Let's wait and see how they behave first, and then decide if we can federate safely" is just as much a "wait and see" stance, and it should take two clicks as well.
Why do we have to get exposed first and react later when we can observe first and then decide if we want it or not?