The fact is that so many people have voted that is impossible for someone to cheat! If there were 20 votes in total I would say that is very easy to cheat, but through our current voting is literally impossible... unless someone has the time for making 100 fake profiles!
But anyway I disagree with some arguments above - people have the right to join the forum just to vote in a competition...
I will bring a real life example:
My uncle was a running for a Mayor. And for all friends of friends of friends etc, who were living at our area but voted for another he took the initiative to personally take their voting cards and arrange to change their voting center. He did this for about 40 people... People that never had anything to do with politics at all and people that he didn't personally know so well! The ending result? He was selected a major with a difference of 28 people!!! Was he legal? Of course he was! Imagine what happens in presidental elections...
So my point is that the rules are: you have an email, you can register and vote! It's no ones fault if someone has a big family or friends that want to support him! Look at it at the good point of view: there are more users registered in the forum as an ending result and maybe more advertisements would come in as a result!
But as said before the good thing about our voting is that the result would be final with more than 100 votes, thus difficult to cheat!