I've posted the whole story here before, but my brother threw his test to get into the gifted program. Fortunately, he only got the idea to "trick" the examiner halfway through, so he still (barely) scored high enough to get into the program. (There's no doubt in my mind that my brother is PG. This kid was writing persuasive essays in fifth grade about the ethics of paying college athletes.) In his case, the motivation was that he had waited all the way through my test (which took something like twice as long as they had told my mother that it would), and then wanted to go home.