From what I've seen from experimenting, the only accounts that seem to have weight on each other on lemmy are my lemmy and kbin accounts. There is definitely room for abuse if I were to make many lemmy accounts accross different instances, which I have seen people abuse, especially on lemmy's version of r/place.
I get maybe 2 upvotes at most, and even then I don't usually upvote my own content because it's unsatisfactory. Upvotes tell me people are engaging with my content and like what they see. It does me no good if I know it's just me. The only time I've ever upvoted my own content is on very small communities where no one on would ever see the content otherwise.
I try to be ethical with my interactions with fediverse, but I definitely see the room for abuse.
From what I've seen from experimenting, the only accounts that seem to have weight on each other on lemmy are my lemmy and kbin accounts.
But I suspect people doing this are more about getting exposure for a point of view or link.
If you post on lemmy and boost on kbin your followers on mastadon I think can see it as a post. So it pushes it all around without a repost and links back to the original.
I think it is pretty good that this stuff works together mostly seamlessly.
I don't think there would be a proper way to enforce it either. The whole idea is to be able to pack your things to any instance at a moments notice. Mixed with how there is no central record of accounts and their IPs and everything is so spread out, there is no way of knowing if someone is a sockpuppet or just a backup
Honestly, this is the one thing that makes me wonder how long Lemmy really has...
Propaganda machines and astro turf farms can essentially move the needle any time they want here. It's enough that I kind of want voting removed completely... It simply has no true validity on Lemmy.