"Honesty tests" are always one of my favorite topics on Slashdot. I took a psychology class on hiring practices in college. The professor mentioned that he had a group of Catholic monks take one of those tests and they all failed. Why? There was a question that asked, "do you know anyone that has used illegal drugs recently?" The monks ran a drug rehabilitation center, so they all answered "yes" to that question.
There are some "gotcha" questions on those tests. The one that comes to mind is, "what do you do if you find a quarter on the street?" There are some answers like, "take it to the police station," etc., but the correct answer is to keep it.
As the article mentions, hiring practices can open a company up to some lawsuits. However, all a company has to do is show data that correlates hiring methods to employee performance. The study has to be double blind, this requires hiring employees that both pass or fail the criteria, and reviewing their work performance later. There is no requirement to show causation, etc., only a correlation is necessary. Most "honesty tests" don't meet that requirement.