I thought this was commonly asked, but maybe it varies by state. In my city in Pennsylvania we get a standardized form that does ask this question. It states, "Would you be more likely to believe the testimony of a police officer or any other law enforcement officer because of his or her job?" [1]
So what kind of answer are they expecting for that question? I genuinely can't tell. It seems obvious to me that people who answer "yes" should be excluded, yet I feel the opposite is true.
[1]http://www.pacode.com/secure/data/234/chapter6/s632.html