Take a look at http://www.yadirectory.com/sug_url.php?cat_id=432 . See the "Answer this simple question to pass the spam test*" at the end.
They got psychic spell wrongly, but what is the answer? Gosh that must be a tough directory to submit to.
Probably everything you write in the box passes the spam validation. But yeah this sure are invalid clicks and is unethical, but could be questioned if its actually against the TOS...
It is no wonder that Google keeps banning Adsense publishers, these are the few bad hats that are causing general mistrust.
haha, thats so funny. i think the answer either Yes or No will be accepted. cause you might click an ad and come back to fill the form. but if it says did you click the ad? means against TOS