The other day one of my posts got a downvote. For reasons, I kinda knew who this downvote came from so I opened up their profile page in another tab, deleted my answer, and that user suddenly got a +1. Yes, it was him/her! Not that I really care, my answer was not particularly good/useful anyway, but it's clear that this "trick" should be blocked somehow. How could this be prevented?
Note: I didn't see the +1 in their rep. tab, because that is not visible to other users. What I saw is that their total reputation increased by one point. Coincidence? I think not.
I do not suggest any specific solution here, I just want to discuss this ability to find who downvoted and its implications. I would also like to hear possible solutions.