Well you would think, but no, they don't...
In the most extreme cases, like a guy teamkilling 3 in a row. Most people will notice that, the people looking at it and the people being victim of the act. That means alot of people saying 1 when the poll enters. And everytime i see a big bunch of people typing 1 in chat, it does usually work.
And another issue here is the fact that people will behave alot more, if they know the polls is still on. That gives them a greater danger of being kicked/banned, which noone likes. Their act has a possible consequence to it. If an admin forget to turn em back on as he left, that means that the danger is limited, since not many people can be arsed to take screenies and make a thread. Since that takes quite alot of time, when u alrdy know that there can be 50 of these kind of guys daily. And thats where the poll helps aswell, its quick and easy.