one way would be a requirement that only participants may vote for winners. there's problems here too, but it would at least prevent sock-puppeting.

edit: revisiting this post, because "prevention" is impposible, but I think a voting requirement that to vote you have to participate could help combat such devious tactics, especially with ranked voting as someone else pointed out.

one way would be a requirement that only participants may vote for winners. there's problems here too, but it would at least prevent sock-puppeting.