[mdmarra]

The moderators do not control this process. There is an automated serial vote detection algorithm.

AFAIK, under no circumstances can a Stack Exchange moderator reverse a vote.

More info on the serial vote detection process here: http://meta.stackexchange.com/questions/126829/what-is-seria...

edit: I just looked at your profile and the deletion/banning of a user account will remove rep too, so I suppose in that manner a mod can "reverse" voting, but it's all or nothing. They have no way to flip individual votes.

edit2: Moderators are not employees of Stack Exchange, they are volunteers elected by the community. Of course employees can change whatever they feel like. This discussion is about the moderators.

[fabian2k]

Moderators can ask someone from the SE community team to look into it, and they can see individual votes and invalidate votes between certain users. The only cases where this actually happens are users using sock puppets to upvote themselves, colleagues/friends/family going through every post and upvoting everything or users targeting a specific user with a large number of downvotes.

The one thing they all have in common is a larger pattern of votes. SE does not act on individual votes, and emailing them about those is a waste of time.

[jacques_chester]

I'm going to guess that anyone with access to the database can do a whole bunch of impossible things.

Such as, I dunno, the people who work at StackOverflow HQ.