Does it work?

[Alex2357]

This simple thing always passes
using (IWebDriver driver = TestHelper.CreateDriver())
{
//var url = @"http://politecaptcha.apphb.com/Home/WithBypass";
//var url = @"http://politecaptcha.apphb.com/Home/WithFallback";
var url = @"http://politecaptcha.apphb.com/Home/WithoutFallback";
driver.Navigate().GoToUrl(url);
var email = driver.FindElement(By.Id("EmailAddress"));
email.SendKeys("a@yahoo.com");

            var feedback = driver.FindElement(By.Id("Feedback"));
            feedback.SendKeys("Test feedback for at@b.com");

            var submit = driver.FindElement(By.CssSelector("input[type=submit]"));
            submit.Click();

        }

[analogrelay]

Does your Web Driver run JavaScript on the page? PoliteCaptcha is designed to only show a CAPTCHA if the browser is not running JavaScript. Most spam bots do not run JavaScript, so if you use a JavaScript-enabled user-agent, this is by-design.

[Alex2357]

Yes, it runs javascript. It is Selenium WebDriver.
Nice to have trivial check for Selenium.

[dotnetprofessional]

If a SPAMer wanted to SPAM your site then using Selenium or similar would easily get around this solution. I cant see how this can be considered a real solution. Granted it stops many bots but if your a site of interest its not much work to spin up Selenium or similar.