My take: They’ll get the data whether or not they are federating. I’ve seen what “data teams” do, and what they will do to get around any lack of cooperation.

So in the defeatist perspective that blocking them or not blocking them has a net zero impact, what other reasons are there to deal with?

Then comes possible abuse. Which may come in the form of a gang of people going against one person on a server. The targeted person should still be able to exercise a block against a whole instance, in this case, meta.

For the server as a whole, it may create additional load. But until we’ve seen what it looks like, I am unsure.

Would not sign any NDA, or pact, or formal agreement.