I will never forget the countless amount of rotten eggs and tomatoes I saw coming my way when I was running Mr. MTF and was actively participating as cheerleader at the same time. Bottom line: it is best to stay neutral when you are running such a contest, abstain from voting, rigging the draw in favor of your vfriends or whatever. It is useless, only creates drama.
Especially when one vote can decide an entire match, an organizer shouldn't get involved.
Even better: never run a contest at all, no one will thank you for that anyway, they will only complain and whine.