Let me put it this way:
Suppose that a person knows that they're the smartest physicist on earth. Such a person would find it very frustrating that their votes on questions and answers can be canceled by a single vote by another individual. What's worse, + votes for answers count for +10 reputation points, while - votes only count for -2, I think. To repair this deficit in the system design the only logical thing to do is to arrange to have multiple accounts.
Is there safeguards in the system for this?