I just tried to check this by looking at one of rimu’s (piefed’s dev) posts and indeed I can see upvotes by piefed.social users from kbin.earth. They’re real usernames too, not just randomly generated ones like I’ve seen proposed in one discussion on private voting.
Or just open the thread on an mbin instance. Here’s everyone that upvoted this thread.
Edit: Downvotes (reduces) are less exposed, but as you said, someone can just run a fedi instance that exposes them to everyone.
Piefed upvotes are private though
Only for untrusted instances iirc.
I just tried to check this by looking at one of rimu’s (piefed’s dev) posts and indeed I can see upvotes by piefed.social users from kbin.earth. They’re real usernames too, not just randomly generated ones like I’ve seen proposed in one discussion on private voting.