As software engineers, we could guess how it could pretty easily be automated to be effectively exhaustive.

Questions are whether there's a will to do that, how decimated their engineering resources are, and what state their culture is in.

I don't know the fediverse protocol but wouldn't it be really easy to check if a link is part of it?

I assume so. Though I expect that this is another one of those things that Musk's attention will wander off somewhere else in a week or two.