I was once pulled over by a Texas DPS cop who asked me that question you hear on the cop shows on television. You know the one, "Do you have any drugs, guns or dead bodies in the car?" I answered truthfully that I don't take drugs or kill people and then had to repeat myself as the officer didn't seem to comprehend that. By the time he had gotten backup, secured me in the back of his police car and torn my car apart I was more than an hour behind my schedule. I have since learned from my local sheriff, who is a friend of mine, that the correct answer is, "Not yet."
That does cause 'em to pause and contemplate, in my experience.