Yeah, since people do tend to abuse everything that we leave a bit open we will try this to see if it will make the site a better place. There is only one way to know, and it's to test it out.
Also ask yourself when you make a thread, are you happy answers like "Yes.", "No.", "Agree." and similar one word replies? I don't think so, and if that's what you want... That's what we have polls for, you simply put the options: Yes, No and Maybe and so on as answers to your poll question. The posting in threads are for discussion, and yeah if people learn how to follow the rules and post things of value in the right place and to follow the guidelines we have, then we wouldn't need to add things like this.