How does this work with moderation? I.e. what happens if I ban the real user from a Lemmy instance? What if I ban the alternate user?
Also, what happens if on Piefed, a user votes for something, then they change the setting and then they vote for the same thing again? How would a Lemmy instance know if it should count the vote or not, since the original user didn't actually vote from Lemmy's point of view?
I'm a little concerned about the precedent this sets. An instance could use this technique to facilitate anonymous commenting or posting in addition to votes.