The best part of the fediverse is that anyone can run their own server. The downside of this is that anyone can easily create hordes of fake accounts, as I will now demonstrate.
Fighting fake accounts is hard and most implementations do not currently have an effective way of filtering out fake accounts. I’m sure that the developers will step in if this becomes a bigger problem. Until then, remember that votes are just a number.
I wonder if an instance could only allow votes by users who are part of instances that require email verification or some other verification method. I would imagine that would heavily help reduce vote manipulation on that particular instance.
You can manipulate the registration indicator. The only reliable way to check would be to try to register an account with every server and see if it works, but you’ll need someone solving CAPTCHAs all day to make that work.
This alone wouldn’t help because I can just set up an instance that requires email verification (or any other kind) and automate it still since I can make infinite emails with my own domain.