The irony being, a motivator hacker could very likely hack this poll.
Just keep changing your user-agent.
It's worthless for anything serious.
Why would you bother to script a full-fledged browser when you can just connect to the site directly through the script, ignoring cookies and/or changing the user-agent string.
Back in my less mature days, I registered 20 AIM accounts, and then wrote a script to have them all log in simultaneously and in one by one start a conversation with a target, and then at my command, flood the target with "warnings", silencing them on AIM. So immature - so fun.
Get an open proxy list, then rig up a simple script to roll through them casting votes.