Kinda weird that this isnt sent to the server and only server. Ig it keeps them honest, but if they really wanted to mess with the numbers, bot accounts do exist
Yes this is something that Kbin users can do (by selecting More > Activity on a post) and I believe Lemmy users can do this too but not with the native inrerface.
Kbin let's you see it all, on a thread-by-thread/comment-by-comment basis. For example I'll (for a moment) downvote your comment. If I check it's activity, this is what I see. https://imgur.com/a/uTgEuUt
Favourites is upvotes, reduces are downvotes, boosts are the twitter/mastodon 'retweet' equivalent. Doesn't matter what instance the comment is on, kbin, lemmy, we can see them for posts and comments. Solely on the thread. I can't go to your profile and see a history of what and who you downvote, but if you downvoted/upvoted me right now for example, I can 100% tell who you are and which you did.