I think all polls must have an Abstain and a Null (I don't know if this is the best term in english) option.

ABSTAIN means you agree with all options. Any result would be OK for you.

NULL means you disagree with all options or want another option to be included. So, you will disagree with any result of the poll. If, NULL "wins", the poll is invalid.

What do you think?

I am not so fond of this. A poll usually starts with a discussion. Any option discussed there is usually included in the poll.

If too many people express there opinion being disagreement with the topic, the first poll wil be: "Do we want this change ?". (your null option). If the vote is yes, then a poll will be posted: "How do we change it".

It's important to express your disagreement in the discussion threads.

Often when there are multiple options to choose from, you will see both an Other (Please explain) and Abstain as options.

-- Ravensfire

Don't have this already?

like Abstain, I have seen it before.