My four top rated answers at Unix & Linux got downvoted, apparently within minutes of each other.
Here is a screenshot.
I don't really mind it, as it doesn't practically affect my reputation... But I wonder if this is an user who has an axe to grind, for some reason. Also, I wonder whether the same user has downvoted other users' answers in the same pattern.
Does the site have some form of auto-detection of this situation, identifying these kinds of patterns (downvoting top answers of a same user, etc.) and having the user flagged for review by moderators or staff? (Perhaps this happened already, just wasn't acted upon.)