Botnets aren't just for DDoS, it can be used for other purpouses - can perform anything its master tells them to - including download BC Client and cast votes.
But I'm not being critic, the issue is that you're using votes on polls generated by the system to a bet system. That's a noway thing to do.
One thing is:
Who will win the next game?
- Team A
- Team B
This is what uncertain future event
Other thing would be:
What's your favorite color?
This is an opinion cast or survey, and it makes no sense to bet on its outcome. Because you're starting a question yourself for a non-event and use the number of replies as the outcome, which becomes a redudancy and a result "ad populum".
Opinions Ad Populum are natural fallacies, like "Many people believes in God" - such has no influence at all to determine whether God exists or not. People beliefs and likes/dislikes doesn't qualify then to create valid results on itsown about anything.