There are several reasons why someone would serially upvote another account. I will list some examples, ranging from good faith to pure evil.
- Gratitude. A user encounters a particularly enlightening answer, and decides to upvote other answers by the same person. This is probably most common with new users.
- Friends voting. Two or more friends have accounts on the same site and vote on each other's posts. While this usually happens in good faith, it actually is dishonest to other users, but I would still not call it disruptive or worthy of suspension.
- Cheating. This is self-explanatory; a user creates a so called "sockpuppet" to increase one's reputation. This is perhaps the most feared behaviour, but I wouldn't say it is as common as its name. Both software and moderators can easily detect this - it's only a matter of time before the "fun" ends.
- Disrupter. This is the most dangerous behaviour by far. The intent here is to make use of everyone's acquaintance with cheaters: by serially upvoting a certain user, the target will be accused of cheating. It is then difficult for a moderator to tell what the purpose was, and a suspension is likely to follow.
I would like to know what is the appropriate way to deal with these particular situations. Of course, all of these examples should be avoided. Sometimes, however, one makes a questionable decision without thinking about its consequences. Personally, I would like to look at the future, but I cannot forget the past. Thank you for taking your time.