A few days ago (after getting some users angry), I got a downvote on a post of mine, which was 5 months inactive. And on two other old posts in the following days (my reputation tab). I doubt this is a coincidence, but I don't want and will not investigate further on this, after all, it's only 3 votes.
The story above, though it's of (absolutely) no importance, sparked up a few hypothetical questions:
This has a key feature: All recently voted-on posts were voted on only once recently. Can the vote filter be bypassed by up- or down- voting on a single user's posts across a long period of time? Like, 60 votes in a month?
What should a user do if he sees many of his posts, active or not, voted on in a row?
Is a user that serial votes another user's votes across a long period of time traceable?