Unless I'm blind, this FAQ never actually states that there is no way to close a poll. It probably should, as we do get asked that question quite a bit -- something in the 'Things to remember' section, perhaps.
"There is no way to close a poll. If you wish to prevent people from being able to continue voting in the poll, you will need edit the entry that contains the poll to remove the poll-related code from the entry. Similarly, you may wish to delete the entry entirely, thus removing the poll from view."
Or something that doesn't suck, LOL. Basically, I think it's a logical path that if they can open a poll, they should be able to close it -- and since they can't, we need to tell them how to achieve the same effect. :)