Although I liked the third option at first, the problem with this is that a lot of (low SP bots / accounts) can sensor just as easy...
My option would be this: let the flag/option cost 2 or 3 times as much as an upvote!
I like to hear your thoughts on these things!?
For the people with the money, cost is irrelevant, so no, I just want to see the option to downvote removed